Two oil tankers have been rocked by explosions in the Gulf of Oman, according to reports, just one month after the U.S. blamed Iran for allegedly sabotaging four other tankers.

The two tankers were allegedly hit Thursday off the coast of the United Arab Emirates—the same area where the other four tankers were supposedly targeted last month. The U.S. Navy’s fifth fleet confirmed it was assisting the two vessels after what it called a “reported attack,” without elaborating on the extent of the damage or the cause of the explosions.

The National—an English-language newspaper based in the UAE—identified one of the ships as the MT Front Altair. The tanker is reportedly “on fire and adrift,” but all 23 crew members are believed to have been rescued. A spokesperson for Taiwan’s state oil refiner CPC, which chartered the tanker, said it was “suspected of being hit by a torpedo.”

The second vessel has been identified as the Kokuka Courageous, which reportedly set sail from the Saudi port of Al Jubail on June 10 and was on course for Singapore. The Associated Press reported that 21 sailors had been evacuated from that ship with one suffering minor injuries.

Iranian state TV reported that the 44 survivors had been evacuated to an Iranian port, and an Iranian news agency tweeted an image of what it said was the Front Altair on fire and billowing with smoke.

Japan’s Trade Ministry confirmed the two vessels had “Japan-related cargo,” raising questions on whether the alleged attacks were meant to send a message to Prime Minister Shinzo Abe who is currently in Tehran seeking to ease tensions between Iran and the United States.

National Security Adviser, John Bolton, said Iran was almost certainly involved in last month’s attacks, but Iran has insisted it hasn’t instructed any form of attack on Gulf shipping or Saudi oil installations.

Benchmark Brent crude spiked by as much 4% in trading following the reported attack to over $62 a barrel.