New U.S. airstrikes targeted Yemen on Tuesday morning, including two areas in the capital, Sanaa, according to the Houthi news agency Saba and Al-Massira TV.

Other raids hit the Bajel region in the Hodeida governorate, as well as a steel mill in the al-Salif area, which was "targeted 12 times," according to the Yemeni rebels' official media.

The Houthis also claimed their third attack in 48 hours on U.S. warships Tuesday, despite intensified American strikes that killed 53 people and injured 98 on Sunday, according to Yemen's Health Ministry. Washington said the strikes also killed "several movement leaders."

The rebels condemned Israel's overnight airstrikes on the Gaza Strip, which killed at least 330 people, according to the Hamas-run health ministry, and vowed to escalate their own operations "in solidarity" with the Palestinians.

"Iran will be held responsible"

Since the start of the war in Gaza, the Houthis have launched several missile attacks against Israel and ships accused of ties to Israel, saying they were acting in solidarity with the Palestinians. These attacks ceased after a cease-fire in Gaza took effect Jan. 19. But on March 11, the Houthis announced they would resume attacks on ships linked to Israel off Yemen's coast, citing Israel's blockade of humanitarian aid to Gaza.

U.S. President Donald Trump announced strikes Saturday against rebel strongholds in Yemen, vowing to use "overwhelming lethal force" to stop attacks in the vital maritime corridor. He also said Monday that Iran would now be "held responsible" for any Houthi attacks.

The Pentagon’s operations chief, Alexus Grynkewich, said Monday that strikes would continue "until the president's objectives are met."

Tehran condemned Trump's "belligerent" remarks in a letter to the U.N. Security Council and warned that any aggression would have "severe consequences" for which Washington would bear "full responsibility."

Massive protests

Following the unprecedented U.S. airstrikes, tens of thousands of Yemenis protested Monday in major rebel-held cities.

In response to the U.S. strikes, the Houthis said Sunday they had targeted the American aircraft carrier USS Harry Truman in the northern Red Sea, firing 18 missiles and a drone.

On Monday morning, they claimed a second attack on the carrier "with many ballistic and cruise missiles as well as drones." On Tuesday, they claimed a third attack within 48 hours. The U.S. has not confirmed any of these attacks.

As tensions rise, the U.N. has urged the U.S. and the Houthis to "cease all military activity." China also called for de-escalation, saying that "the situation in the Red Sea and the Yemeni issue have complex causes and must be resolved through dialogue."

Houthi attacks have disrupted shipping in the Red Sea and the Gulf of Aden, prompting the U.S. to establish a multinational naval coalition and strike rebel targets in Yemen, sometimes with U.K. support.

Yemen, one of the poorest countries on the Arabian Peninsula, has been embroiled in civil war since 2014 between the Houthis and the Saudi-backed government. The conflict has killed hundreds of thousands and created one of the world's worst humanitarian crises, according to the U.N.