The Winning ExchangeIranian-backed Houthis launched another attack on merchant shipping Tuesday just hours after the U.S. preemptively struck missiles in Yemen that were prepared to launch, according to a statement from U.S. Central Command. 

U.S. Central Command said there were no injuries reported from the merchant ship.  

The statement on Tuesday said the U.S. had struck four anti-ship ballistic missiles that were an imminent threat to U.S. Navy ships and commercial vessels in the Red Sea. 

But in the afternoon, the Houthis hit another merchant ship in the Red Sea, a sign the group is not stopping their attacks on shipping despite a series of strikes by the U.S. The Houthis have said they will attack ships connected to Israel and its allies, but U.S. officials have said many of the ships attacked have no connection to Israel. 

"We have seen some additional lower scale retaliatory strikes by the Houthis in the last few days, much smaller than what we have seen before and none of them effective," National Security Council coordinator for strategic communications John Kirby said Tuesday. 

Last week, the U.S. and U.K. with support from other nations struck just under 30 locations targeting "radar systems, air defense systems, and storage and launch sites for one way attack unmanned aerial systems, cruise missiles, and ballistic missiles," according to a statement from U.S. Central Command. 

Kirby said he thinks it's too soon to say the continued attacks by the Houthis indicate the coalition strikes were not effective. 

"We believe that we did have a good effect with those strikes in terms of disrupting and degrading their capability to conduct military offensive operations," Kirby said. 

The Biden administration has emphasized it does not want Israel's war with Hamas to turn into a wider regional conflict. However, the Houthi attacks on commercial shipping combined with the ongoing attacks by Iranian-backed militias on U.S. forces in Iraq and Syria show the instability in the Middle East already extends farther than Israel. 

In:
• Red Sea
• Houthi Movement

Eleanor Watson

Eleanor Watson is a CBS News reporter covering the Pentagon.

Twitter