The Pentagon is deliberating whether to directly strike Houthi rebel military targets in Yemen in response to the Iranian-backed militia’s escalating attacks on military and commercial shipping in the Red Sea.

Biden administration officials told Semafor they’re increasingly concerned that the Houthis, and their sponsors in Tehran, are trying to undermine global maritime trade, both to undercut trade to Israel and to raise the costs to the U.S. and its allies for supporting the Jewish state’s now 11-week war in Gaza against the Palestinian militant group Hamas. Already, some global shipping lines are diverting their cargo traffic away from the Red Sea and Suez Canal to routes circling the Horn of Africa, which significantly increases transit times and costs.

But U.S. officials say they’re weighing a strike on the Houthis against their fears of potentially fueling a broader war against Iran and its proxies. Biden administration officials have repeatedly said their priority is keep the Middle East conflict solely focused on backing Israel’s campaign to dislodge Hamas from its base in Gaza, though they haven’t ruled out more aggressive military operations. Iranian-backed militias have also launched dozens of attacks on U.S. military bases in Iraq and Syria over the past two months.

“As we’ve demonstrated in the past… our military will not hesitate to take action where we deem it necessary and appropriate, including to protect against actions in the maritime domain that could threaten our troops,” Pentagon spokesman Gen. Patrick Ryder said in Washington this week in reference to the Houthi attacks.

U.S. and allied forces have intercepted Houthi missiles and attack drones in recent weeks that the Pentagon believes were targeting Israel. The Yemeni army has vowed to militarily back Hamas following its October 7 attack on Israel. And the Houthis have widened their campaign to target commercial ships that the militia alleges were heading towards Israeli ports.

On Tuesday, the Houthis struck a Norwegian-flagged tanker, the Strinda, with a cruise missile. Last month, they seized a cargo ship allegedly partly owned by an Israeli businessman and took its 25-person crew captive. “If Gaza does not receive the food and medicine it needs, all ships in the Red Sea bound for Israeli ports, regardless of their nationality, will become a target for our armed forces,” Houthi spokesman Yehia Sareea told Yemeni television this week.

The U.S. has deployed two carrier strike groups to the Mideast since early October and has the assets to target Houthi missile batteries and radar systems inside Yemen. But so far, the Pentagon has stood down due to these fears of escalation, according to U.S. officials. The U.S. hasn’t directly attacked Houthi military positions in Yemen since 2016, when the Pentagon destroyed one of the militia’s coastal radar installations using Tomahawk missiles in response to attacks on U.S. naval ships.

The Pentagon’s deliberations on the Houthis are occurring as U.S. officials seek to widen the numbers of countries participating in a maritime coalition, called Combined Task Force 153, which is charged with policing the Middle East’s key waterways and choke points — including the Straits of Hormuz and Bab el-Mandeb strait.