Four Limpet mines were placed by trained divers who were deployed from fast boats, according to the preliminary findings.

Initial findings of an investigation led by the United Arab Emirates of May 12 attacks on oil tankers point to the likelihood that a state was behind the bombings, the UAE said.

The UAE along with Saudi Arabia and Norway presented the preliminary findings during a briefing to the UN Security Council, which will also receive the final results of the probe to consider a possible response.

The United States has accused Iran of being behind the attacks on the four oil tankers off the Emirati coast, which came at a time of escalating tensions between Tehran and Washington.

The four vessels - two Saudi-flagged, a Norwegian-flagged and an Emirati-flagged - were damaged by explosions that took place within UAE territorial waters, off the port of Fujairah.

After assessing the damage and carrying out chemical analysis, the UAE told the council that the attacks were sophisticated and of the type most likely carried out by state services.

"While investigations are still ongoing, these facts are strong indications that the four attacks were part of a sophisticated and coordinated operation carried out by an actor with significant operational capacity, most likely a state actor," said a statement from the UAE, Saudi Arabia and Norway.

The initial findings showed that it was "highly likely" that four Limpet mines, which are magnetically attached to a ship's hull, were used in the attacks, placed by trained divers who were deployed from fast boats, according to the preliminary findings.

The UAE believes the attacks required intelligence capabilities to pick the four oil tankers as targets, one of which - a Saudi ship - was at the opposite end of the anchorage area at Fujairah from the three other tankers.

Iran has rejected accusations that it was behind the sabotage and diplomats said there was no mention of Iran's possible role during the briefing by the UAE.

Saudi Arabia told reporters that Tehran was nevertheless the most likely culprit.

"We believe the responsibility for this attack lies on the shoulders of Iran," Saudi Arabia's UN Ambassador Abdallah Al Mouallimi told reporters after the briefing.

Saudi Arabia maintains the attacks affect the safety of international navigation and the security of world oil supplies, requiring a response from the Security Council.

US National Security Advisor John Bolton said last week that Iranian mines were likely used in the attacks.

"There's no doubt in anybody's mind in Washington who's responsible for this," Bolton said last week during a visit to Abu Dhabi.

US Secretary of State Mike Pompeo has said that Iran was trying to raise the price of oil as Washington works to end Iran's exports of crude.