The U.S. on Sunday accused Iran of being behind an attack on an Israeli-linked Mercer Street oil tanker last week that killed two workers on board.

"We join our partners and allies in our strong condemnation of the attack against the Mercer Street, a commercial ship that was peacefully transiting through the north Arabian Sea in international waters," Secretary of State Antony Blinken said in a statement.

"Upon review of the available information, we are confident that Iran conducted this attack, which killed two innocent people, using one-way explosive UAVs, a lethal capability it is increasingly employing throughout the region."

On Thursday, the Liberian-flagged Mercer Street ship was attacked, with two crew members, British and Romanian, being killed as a result. The U.S. military said on Saturday that it had determined the attack was carried out by a drone strike.

The ship is owned by Maritime Zodiac which Israeli billionaire Eyal Ofer owns through his company the Zodiac Group shipping company.

Both Israel and the U.K. have accused Iran of carrying out the attack. Iran has denied any involvement.

"I declare unequivocally: Iran is the one that carried out the attack on the ship," adding that intelligence supports his claim," Israeli Prime Minister Naftali Bennett said.

"There is no justification for this attack, which follows a pattern of attacks and other belligerent behavior," Blinken added in his statement. "These actions threaten freedom of navigation through this crucial waterway, international shipping and commerce, and the lives of those on the vessels involved."

Blinken stated that the U.S. would be working with its partners and governments in the region to determine its response to this attack.