Iran and allied militias in the Middle East, along with at least one U.S. ally, condemned the U.S.-led airstrikes against Houthi targets in Yemen on Friday and warned that they risked causing a broader conflict in the region.

The strikes came after a series of Houthi attacks against ships in the Red Sea. The Houthis have said they are targeting Israeli ships and vessels headed to Israel in an effort to support Palestinians in the Gaza Strip, who have been under relentless Israeli bombardment for nearly 100 days, although some Houthi targets have had no clear connection to Israel.

Israel’s military offensive in Gaza since Oct. 7 has killed more than 23,000 Palestinians, according to the Gaza Health Ministry. The Israeli war came in response to the Oct. 7 attack by Hamas, the armed group that controls Gaza, that left some 1,200 people dead, according to Israeli officials.

A Houthi spokesperson, Mohammed Abdul Salam, said on social media that the group would remain by Gaza’s side. He said there was no justification for the strikes on Yemen because the Houthi actions did not threaten international shipping and vowed that the group would continue to target Israeli ships and those heading to Israel.

In an interview with Al Jazeera, Abdul Salam signaled that Houthi forces would retaliate for the U.S. strikes, saying, “Now, the response no doubt is going to be wider.”

Hamas and Hezbollah, which like the Houthis are backed by Iran, also condemned the strikes. Hamas called them an “act of terrorism,” a violation of Yemen’s sovereignty and “a threat to the security of the region.”

Nasser Kanani, a spokesperson for the Iranian Foreign Ministry, denounced the strikes as “a violation of international laws” and said they “will have no result other than fueling insecurity and instability in the region.”

Even one close U.S. ally, Oman, which often mediates between the Houthis and international parties, expressed concern. Its criticism reflected the fear that the U.S.-led action would not deter the Houthis but would only inflame regional conflict.

“It is impossible not to denounce that an allied country resorted to this military action, while meanwhile, Israel is continuing to exceed all bounds in its bombardment, brutal war and siege on Gaza without any consequence,” Oman’s Foreign Ministry said in a statement.

In Bahrain, another U.S. ally, people took to the streets Friday to protest their country’s involvement in the military coalition, according to Bahraini activists who shared pictures of the demonstrations. Amid popular anger over its participation in the coalition, the Bahraini government has not independently acknowledged its role but was named in the joint statement announcing the strikes.