Tensions escalated near the Strait of Hormuz after a ship anchored off the United Arab Emirates was seized and taken toward Iran and another cargo vessel sank following an attack near Oman, authorities said Thursday. The incidents came amid continued wrangling between the United States and Iran over keeping the waterway open, and as U.S. President Donald Trump met with Chinese leader Xi Jinping in Beijing.

The UK Maritime Trade Operations center said it received reports that the ship seized Thursday was taken by unauthorized personnel while anchored 38 nautical miles (70 kilometers, 44 miles) northeast of the UAE port of Fujairah, an oil export terminal repeatedly targeted during the war with Iran. The center did not name the ship, and said it was investigating what happened. The British military said the vessel was heading toward Iranian waters.

Separately, Indian authorities said an Indian-flagged cargo ship sank off the coast of Oman after an attack sparked a fire aboard the vessel. They said the ship was en route from Somalia to Sharjah, another UAE port, and did not identify who attacked it. Mukesh Mangal, a senior official in India’s shipping ministry, said the attack on the Haji Ali happened Wednesday and that Oman’s coast guard rescued all 14 Indian crew members.

India’s foreign ministry called the incident “unacceptable” and condemned continued attacks on commercial shipping and civilian mariners. The ministry did not say who carried out the attack.

The flare-up also unfolded at a tense diplomatic moment. Iranian semiofficial news agencies reported that Chinese ships began passing through the strait late Wednesday under new Iranian protocols, saying Tehran agreed to facilitate the passage of several Chinese vessels after requests from China’s foreign minister and Beijing’s ambassador to Iran. The report said the ships began their passage as Trump arrived in China.

Hours before the reported UAE seizure, Prime Minister Benjamin Netanyahu announced he had quietly visited the UAE during the Israeli-U.S. war with Iran, though the UAE denied it. Yoel Guzansky, a senior researcher at the Institute of National Security Studies in Tel Aviv, said Netanyahu’s decision to go public was likely aimed at rallying support for his flagging party ahead of Israeli elections. Guzansky said the UAE was trying to highlight cooperation with Israel while drawing a distinction from Netanyahu’s government, adding that many in the UAE are against Israel’s policies in Gaza.

Iran, meanwhile, set conditions for renewed talks with the United States, saying it would not enter additional negotiations unless five conditions were met, including paying reparations for the war and accepting Iran’s sovereignty over the Strait of Hormuz, according to Iran’s semiofficial Fars news agency. The White House was unlikely to accept those demands, which would effectively formalize Iran’s control over a waterway that had been open to international traffic before the war, the report said.

Iranian officials also reiterated their stance on the waterway. Mohammadreza Aref, Iran’s senior vice president, said Thursday that the strait belongs to Iran and that Tehran would not give it up “at any price,” according to state TV. “It has always been our property,” Aref said, as reported by the Associated Press.

Iran also defended the right to seize ships. A judiciary spokesperson told the state-owned Iran Daily newspaper that Iran has the legal and judicial right to seize oil tankers in the strait connected to the United States because the U.S. violated international maritime laws and committed piracy. The spokesperson, Asghar Jahangir, did not explicitly refer to the tanker seized Thursday. The report also noted that Iran last week seized several ships, including a tanker identified as the Ocean Koi, saying it was trying to disrupt oil exports and Iranian interests, and that the United States sanctioned the Ocean Koi in February as part of a “shadow fleet” transporting Iranian oil.

On Thursday, the top U.S. commander in the Middle East told lawmakers that he believes Iran’s military capabilities have been “dramatically degraded,” but said Iran’s leaders affect shipping in the strait through rhetoric. “Their voice is very loud, and the threats are clearly heard by the merchant industry and the insurance industry,” Adm. Brad Cooper said, adding that the U.S. has the military power to permanently reopen the strait and escort ships while deferring to policymakers amid “time of sensitive negotiations.”