Yemen's Houthi rebels stormed the headquarters of the United Nations' Human Rights Office in the capital, Sanaa, seizing documents, furniture and vehicles, a senior U.N. official said Tuesday.

The seizure was the latest move in a crackdown by the Houthis on people working with the U.N., aid agencies and foreign embassies. The crackdown comes as the Iranian-backed rebels have been targeting shipping throughout the Red Sea corridor over the Israel-Hamas war in the Gaza Strip.

U.S.-backed Syrian fighters have carried out a rare attack in eastern Syria, striking at three posts manned by pro-government gunmen and claiming that they killed 18 of them in a major escalation near the border with Iraq.

The renewed clashes in Syria's eastern oil-rich province of Deir el-Zour came amid high tensions in the region following last month's killings of a top commander of Lebanon's militant Hezbollah group in Beirut and the political leader of the Palestinian Hamas group in Iran. Israel was blamed for both attacks, and Iran and Hezbollah have vowed to retaliate.

A ship in the Red Sea was targeted in a third attack suspected to have been carried out by Yemen's Houthi rebels Tuesday in their campaign of assaults over the Israel-Hamas war, officials said.

The attacks come as the rebels' main sponsor, Iran, weighs possible retaliation against Israel over the assassination of Hamas official Ismail Haniyeh in July, which has renewed fears of a wider regional war in the Middle East.

Israel's Prime Minister Benjamin Netanyahu and Defense Minister Yoav Gallant have exchanged criticism over stalled talks for a ceasefire deal that would free hostages held in Gaza.

"The reason a hostage deal is stalling is in part because of Israel", Israeli media, including television channel Kan, reported Gallant saying in a private briefing for a parliamentary committee on Monday.

The White House has said that it shares the Israeli intelligence assessment that Iran could launch a strike on Israel as soon as this week.

National security spokesperson John Kirby told reporters Monday that “it is difficult to ascertain at this particular time if there’s an attack by Iran or its proxies what it could look like,” but that the U.S. and its allies were preparing for “a significant set of attacks.”

Iran on Tuesday rejected Western calls to stand down its threat to retaliate against Israel for the killing of Hamas political leader Ismail Haniyeh in Tehran late last month.

"The declaration by France, Germany and Britain, which raised no objection to the international crimes of the Zionist regime, brazenly asks Iran to take no deterrent action against a regime which has violated its sovereignty and territorial integrity," foreign ministry spokesman Nasser Kanani said in a statement.

A 5.5 earthquake hit central Syria late Monday, with the shock felt in neighboring Lebanon, official media in both countries said.

German Chancellor Olaf Scholz on Monday expressed "great concern" about the "spiral of violence" in the Middle East in a phone call with Iranian President Masoud Pezeshkian, his spokesman Wolfgang Buechner said in a statement.

Scholz "appealed to President Pezeshkian to do everything possible to prevent a further military escalation", expressed "great concern about the danger of a regional conflagration in the Middle East" and said "the spiral of violence in the Middle East must be broken now".

Frequent beatings, overcrowding, withholding of basic rations. Released Palestinians have described to The Associated Press worsening abuses in Israeli prisons crammed with thousands detained since the war in Gaza began 10 months ago.

Israeli officials have acknowledged that they have made conditions harsher for Palestinians in prisons, with hard-line National Security Minister Itamar Ben Gvir boasting that prisons will no longer be "summer camps" under his watch.

Israeli Defense Minister Yoav Gallant said Monday that he had wanted to attack Lebanon as early as October 11, 2023.