The United States launched large-scale airstrikes in Yemen over the weekend, killing at least 31 people, including children, days after the Houthis vowed to resume attacks on Israeli-linked ships in the Red Sea to show solidarity with Palestinians amid the ongoing blockade in Gaza.

Saturday's campaign, which one US official told Reuters might continue for weeks, was the first in Yemen since US President Donald Trump assumed office in January and redesignated the Houthi group as a "foreign terrorist organization".

At least 31 were killed and 101 others injured in the strikes, mostly women and children, Anees al-Asbahi, spokesman for the Houthi-run health authorities, said on Sunday.

"The explosions were violent and shook the neighborhood like an earthquake. They terrified our women and children," a resident of the Yemeni capital Sanaa, who gave his name as Abdullah Yahia, told Reuters.

In a statement, the Houthis' political bureau described the US attacks as a "war crime".

"Our Yemeni armed forces are fully prepared to respond to escalation with escalation," it said.

Palestinian group Hamas also criticized the US strikes, branding them "a stark violation of international law and an assault on the country's sovereignty and stability".

On Tuesday, the Houthis said they would resume attacks on any Israeli ships in the Red Sea, Arabian Sea, the Gulf of Aden and the Bab al-Mandab Strait until aid was again allowed into the Gaza Strip. The vital route is used by nearly 12 percent of the world's shipping traffic.

Since November 2023, the Houthis have launched dozens of drone and rocket attacks against Israel-linked ships, forcing many companies to take costly detours around southern Africa and setting the US military on an expensive campaign to intercept missiles and drones. The group stopped its attacks on Jan 19 when the Gaza ceasefire deal took effect.

In a social media post on Saturday, Trump vowed to "use overwhelming lethal force until we have achieved our objective". He warned Houthis "Your time is up" and if the attacks did not stop "starting today ... Hell will rain down upon you like nothing you have ever seen before".

He warned Iran that it must "immediately" stop its support to the Houthis and vowed to hold Iran "fully accountable" for actions of the Houthis.

Meanwhile, Iran's Foreign Ministry on Sunday condemned the deadly US strikes, calling them a "gross violation of the principles of the UN Charter". In a post on X, Foreign Minister Abbas Araghchi said the Trump administration has "no authority, or business, dictating Iranian foreign policy".

In an apparent sign of efforts to improve ties with Russia, US Secretary of State Marco Rubio spoke on Saturday with Russian Foreign Minister Sergey Lavrov by telephone about the strikes.

"Lavrov stressed the need for an immediate cessation of the use of force and the importance for all sides to engage in political dialogue in order to find a solution that would prevent further bloodshed," the Russian Foreign Ministry said on Sunday.

Nabeel Khoury, a former US diplomat, told Al Jazeera that Trump's decision to launch attacks against the Houthis was misguided, and would not subdue the group.

"If you think that Hamas, living and fighting on a very small piece of land, totally surrounded by land, air and sea, and yet, 17 months of Israeli bombardment did not get rid of them. The Houthis live in a much more rugged space, mountainous regions — it would be virtually impossible to eradicate them," he said.

"So there is no military logic to what's happening, and there is no political logic either," he said.

"For our president who came in wanting to avoid war and wanting to be a man of peace, he's going about it the wrong way. There are many paths that can be used before you resort to war," Khoury said.

Trump's statement did not reference the conflict in Gaza.

In the Gaza Strip, authorities said nine people, including journalists, were killed in Israeli strikes on Saturday, attacks which could further endanger a fragile truce there.

The Palestinian Journalists Syndicate said an editor and three photo journalists were among those killed. One was a drone photography specialist.

The syndicate's deputy head in Gaza, Tahseen al-Astal, told AFP that the attack targeted a charity vehicle in which the journalists were preparing reports and documentaries on the work of charitable organizations during Ramadan.

Following the deadliest strikes since the ceasefire took hold on Jan 19, Hamas accused Israel of a "blatant violation" of the truce.

The truce's first phase ended on March 1 without agreement on the next steps. A senior Hamas official said last week that fresh talks had begun in Doha, with Israel also sending negotiators.

Israel is prepared to continue Gaza ceasefire talks based on the mediators' response to a US proposal for the release of 11 living hostages and half of the deceased, Israeli Prime Minister Benjamin Netanyahu's office said on Saturday.

However, Hamas said on Saturday it will only release an American-Israeli and the bodies of four other hostages if Israel implements the ceasefire agreement.

A senior Hamas official said long-delayed talks over the ceasefire's second phase would need to begin on the day of the release and last no longer than 50 days, The Associated Press reported. Israel also would need to stop barring the entry of humanitarian aid and withdraw from a strategic corridor along Gaza's border with Egypt. Israel has said it won't withdraw from there, citing the need to combat weapons smuggling.

Agencies and Xinhua contributed to this story.

cuihaipei@chinadaily.com.cn