Iran on Saturday rejected as "baseless" allegations by G7 foreign ministers that it was behind a deadly drone attack on a tanker off Oman last week.

Tehran has strongly denied having any link to the July 29 attack on the MT Mercer Street, an oil products tanker operated by Israeli-controlled Zodiac maritime, but has faced an increasing wave of accusations in recent days from Israel and its allies.

A British security guard and a Romanian crew member were killed in the attack.

"We strongly condemn the baseless statement by the foreign ministers of the G7 and the European Union's high representative for foreign affairs in which they have directed baseless accusations at the Islamic Republic of Iran," foreign ministry spokesman Saeed Khatibzadeh said in a statement.

The tanker attack and the accusations against Iran were a manufactured "scenario" with a "notable" timing, he said, as they came before Iran's new President Ebrahim Raisi took the oath of office.

Ultraconservative Raisi was inaugurated on August 3 by Iran's supreme leader Ayatollah Ali Khamenei, and sworn in by parliament two days later, taking over from moderate president Hassan Rouhani.

"For experts and those who know the history of this region, it is not a new thing that the Zionist regime would design such conspiracies," Khatibzadeh said.

Citing the results of a probe, the US Central Command said on Friday that remnants from one of three explosives-laden drones that targeted the MT Mercer Street indicated it was produced in Iran.

Iran's military denied the allegations.

"The Americans say they have found parts of Iran's drones in the water, and this is their evidence. But what laboratory has determined (the drones) belong to Iran?," military spokesman Brigadier General Abolfazl Shekarchi was quoted by IRNA news agency as saying.

"This is the Americans' method, to weave stories and use it to accuse Iran... this is the method they have chosen to pressure Iran," he added.