Today's D Brief: US strikes Yemen, Iraq, and Syria; Senate unveils Ukraine, Israel, border bill; China's busy shipyards; And a bit more.

The U.S. and allies conducted several series of airstrikes inside and around Yemen this weekend as the White House continues walking the fine line of defending its assets in the region without provoking a wider conflict, while Israel’s war with Hamas enters its 122nd day.  

On Sunday, U.S. forces near Yemen shot down a land attack cruise missile and an anti-ship cruise missile fired by the Houthis, military officials at Central Command said Sunday. Later that morning, U.S. forces conducted more airstrikes on four anti-ship cruise missiles that were “prepared to launch against ships in the Red Sea” from Houthi-controlled areas of Yemen.

The British joined the U.S. again to conduct several more airstrikes on Houthi targets inside Yemen on Saturday. Similar to the prior joint U.S.-U.K. strikes nearly two weeks ago, a coalition of friendly nations—Australia, Bahrain, Canada, Denmark, the Netherlands, and New Zealand—assisted in unspecified supporting roles, CENTCOM said in a statement afterward. 

Those strikes hit 36 Houthi targets across 13 locations as a response to ongoing attacks on international merchant vessels and U.S. Navy ships in the region, U.S. officials said. Targets included “underground storage facilities, command and control, missile systems, UAV storage and operations sites, radars, and helicopters,” according to CENTCOM. 

“The Houthis’ now more than 30 attacks on commercial vessels and naval vessels since mid-November constitute an international challenge,” officials from all participating countries said in a joint statement. “We remain committed to protecting freedom of navigation and international commerce and holding the Houthis accountable for their illegal and unjustifiable attacks on commercial shipping and naval vessels,” they said. 

“We will not hesitate to defend lives and the free flow of commerce in one of the world's most critical waterways,” Pentagon chief Lloyd Austin said in his own statement. 

About five hours earlier, the U.S. military destroyed six Houthi anti-ship cruise missiles in another pre-emptive or self-defense strike inside Yemen. 

Friday was particularly busy for U.S. forces around Yemen as well, with sailors on board the USS Carney having shot down a drone over the Gulf of Aden; separate U.S. airstrikes about six hours later destroyed Houthi drones allegedly just prior to launch; and American troops shot down another seven drones launched over the Red Sea just after 9 p.m. local time, according to CENTCOM. 

Developing: The Iran-backed Houthis are reportedly considering cutting undersea cables running beneath the Red Sea, according to a semi-veiled threat posted to social media. The warning came from a Yemeni telecom aligned with the United Nations-backed government (that is, not aligned with the Houthis) and in response to the initial social media threat posted in late December.

“[A]s many as 16 of these submarine cables—which are often no thicker than a hosepipe and are vulnerable to damage from ships’ anchors and earthquakes—pass through the Red Sea towards Egypt,” the Guardian, reported Monday. “One of the most strategic is the 15,500-mile (25,000km) Asia-Africa-Europe AE-1 that goes from south-east Asia to Europe via the Red Sea.”

There is a precedent: “In 2013, three divers were arrested in Egypt for attempting to cut an undersea cable near the port of Alexandria that provides much of the internet capacity between Europe and Egypt,” the Guardian reports. More here.

Welcome to this Monday edition of The D Brief, brought to you by Ben Watson with Jennifer Hlad. Share your newsletter tips, reading recommendations, or feedback for the year ahead here. And if you’re not already subscribed, you can do that here. On this day in 1918, the U.S. military notched its first aerial victory when Stephen Thompson shot down a German Albatros D.III fighter.

The U.S. military carried out a separate and much more widespread series of attacks against Iranian forces’ facilities and Iran-backed militias inside Iraq and Syria on Friday afternoon. Those strikes were described as a direct response to the January 28 deaths of three American troops from an Iranian-provided drone strike at a rural base in Jordan, U.S. officials said Friday. 

Some 85 different targets on both sides of the Iraq-Syria border were hit, including several that triggered large secondary explosions, according to observers and U.S. defense officials. Four sites inside Syria were hit, while three inside Iraq were targeted. 

View one post-strike satellite image from Iraq, captured Sunday by Planet Labs, shared via social media by The War Zone, here.

Why wait five days to strike back? “This was designed around the weather,” a U.S. official told reporters afterward on Friday. “Good weather presented itself today; and as a result, this took place,” he said. 

One of those allegedly killed was an Iran-backed leader named Ali Hosseini, who fronted the Fatemiyoun militia in Deir Ezzor, Syria, and had been known as a close associate of former Iranian paramilitary chief Qasem Soleimani. Other notable alleged Fatemiyoun deaths from those Friday U.S. strikes include Mohammed Ali Akbari, Hamzah Ali, and Mohammed Reza Sadat Alavi. 

Developing: Iran-backed militias attacked U.S.-backed Syrian Democratic Forces with exploding drones on Sunday, killing six fighters, the group’s spokesman said on social media Monday. “The Iranian-backed militias used the Syrian regime-controlled areas in Deir Ezzor as a staging ground for the terrorist attack that targeted our Commando Academy,” where the six were killed, Farhad Shami of the SDF said. 

More attacks against the SDF may be on the horizon because, as one regional observer suggested, doing so does not directly signal a confrontation with the U.S., but rather with U.S.-backed forces inside Syria. 

Expert reax: “Since the U.S. strikes in Syria and Iraq on Friday night, Iran-directed militias have launched at least 4 attacks,” including the Sunday strike against the SDF, which operates out of a base that also includes U.S. personnel, Charles Lister of the Middle East Institute said Monday. 

Big picture consideration: “In the past 10 days, I've heard officials from 3 key Middle East allies warn that amid events since Oct 7, the region has a ‘pre-9/11’ feel—with anger & hostility towards the US at an alarming level,” Lister said Saturday, and cautioned, “I'm not sure there's any recognition of that at all in policymaking circles.”

One think tank advocating restraint is hosting an event Tuesday morning asking naively, “Does the Middle East still matter?” Defense Priorities will host a virtual discussion with four analysts to assess the question, along with other linked concerns, such as, “What interests justify the presence of 46,000 U.S. forces so far from home, along with these new strikes and their attendant risks? As a net exporter of oil today, is protecting Persian Gulf oil still a priority for the United States?” That is scheduled for 11 a.m. RSVP, here. 

Additional reading: “Saudi companies to make parts for Lockheed's THAAD defense system,” Reuters reported Monday.

Ukraine’s president is about to replace his top military officer, the Washington Post reported Friday after days of speculation that something along those lines was in the works. White House officials were reportedly neutral on the decision, claiming that such calls are entirely up to Ukraine’s leadership. 

Meanwhile, Ukraine is racing to build a million explosive drones since more weapons and ammo from the U.S. seems unlikely to happen anytime soon. In the process, “Ukrainian drone producers are keeping their operations smaller, with a few dozen employees in one building, a few dozen more in another, in hopes of keeping their work hidden,” the Wall Street Journal reported Saturday. 

About that lagging U.S. aid: Senators finally released their bipartisan plan linking military support for Israel, Ukraine, the Indo-Pacific, the Red Sea (new), and strict changes to U.S. border policy and security. The text allocates more than $20 billion for the border, $14 billion for Israel, almost $2.5 billion for CENTCOM, almost $5 billion for the Pacific, and just over $60 billion for Ukraine. Reuters has more.

Senate forecast: It could come up for an initial vote as soon as Wednesday, Leader Chuck Schumer said in a lengthy statement. 

House forecast: “If this bill reaches the House, it will be dead on arrival,” said Republican Speaker Mike Johnson, who wrote on social media, “This bill is even worse than we expected, and won’t come close to ending the border catastrophe the President has created.” 

Editor’s note: The U.S. has struggled with immigration from its southern border since at least the 1980s (see this analysis from Rand, or this from the Center for Immigration Studies, or this from the Council on Foreign Relations, e.g.); and far-right elements of the U.S. have been using the issue as a rallying cry for intolerance and often violent policies almost every decade since, as we learned last week in our latest podcast discussion with terrorism scholars Bruce Hoffman and Jacob Ware of the Council on Foreign Relations, whose book, “God, Guns, and Sedition: Far-right Terorrism in America” was published in January.

And lastly: China is building military ships much more quickly than the United States, and while the commander of the U.S. Navy’s Pacific Fleet is “confident that we would prevail in combat,” he’s not so sure about the future. 

“We are not overmatched, but I don’t like the pace of the trajectory,” Adm. Samuel Paparo, Jr. said Thursday, during a hearing on his nomination to lead Indo-Pacific command.  

Paparo was responding to a question from Sen. Dan Sullivan, R-Alaska, about China’s “rapid naval buildup,” which he said has underscored the U.S.’s “shipbuilding deficiencies.” 

“Numerically, they now have a larger Navy, roughly 370 ships to our 291 ships. Last year, they added 30 ships to their fleet; 15 were large surface combatants including cruisers, destroyers and another aircraft carrier. We added two,” Sullivan said. 

Defense One’s Lauren Williams has more on the hearing, here, including details on what Paparo named as his would-be top priority as INDOPACOM chief: Equipping Guam with an integrated air and missile defense system.