UN Secretary General Antonio Guterres said the truth needed to be "clearly established".
"We consider it necessary to refrain from hasty conclusions".
Still on another front, Iran categorically rejected as "unfounded" US claims that it is responsible for the attacks, warning of "another Iranophobic campaign" being waged by Washington and its allies. The aim, as the United States has made clear, is to reduce Iranian oil exports, which count for the overwhelming share of the country's export earnings, to zero.
On Friday, Donald Trump told Fox News that Iran "did do it". He abandoned a nuclear deal that was brokered by the Obama administration and significantly tightened sanctions on Iran. The Russian Embassy in Tehran said that the crew will fly from Bandar Abbas in Iran to Dubai and then to Russia. "I guess one of the mines didn't explode and it's probably got essentially Iran written all over it", POTUS said. "And you saw the boat at night trying to take the mine off and successfully took the mine off the boat, and that was exposed", he said.More news: Mike Huckabee: Sarah Sanders running for Arkansas governor 'could happen'
As US-Iranian tensions soared, Trump dismissed previous threats by Tehran that in case of conflict it could block the Hormuz Strait - a narrow seaway vital to the world's oil supplies.
This handout powerpoint slide provided by US Central Command damage shows an explosion, left, and a likely limpet mine can be seen on the hull of the civilian vessel M/V Kokuka Courageous.
Three sources in the Gulf said few options exist: Gradually introduce the escort system used during the Iran-Iraq "Tanker War" in the 1980s and more recent Somali pirate attacks, adopt new rules of engagement, and conduct mine-sweeping operations.
Asked whether he was considering sending more troops or military capabilities to the Middle East, Shanahan said: "As you know we're always planning various contingencies".
While the United Kingdom government is fuelling the USA version of events pointing the finger at Iran for the attacks in the tankers, Labour Party leader Jeremy Corbyn has questioned that assessment, insisting on the need for credible evidence.
7 May: Iran says it plans to withdraw from parts of the 2015 nuclear agreement with major world powers.More news: Sarri Juventus deal done - media - English
Pompeo's inclusion of the Afghanistan attack in his list of six Iranian incidents has raised eyebrows in Congress, where he and other USA officials have suggested that the administration would be legally justified in taking military action against Iran under the 2001 Authorization of Military Force, or AUMF.
According to the USA account of events, United States naval forces in the region received distress calls from the Norwegian-owned Front Altair at 6.12am (local time) and from the Japanese-owned Kokuka Courageous at 7am, following explosions, and moved towards the area. The crew from Kokuka Courageous were picked up and handed to a US Navy ship on Thursday. Both Iran and the United States later released pictures showing rescued crew members on board their vessels.
All the 21 Filipino sailors were rescued from Kokuka Courageous to a US warship, the USS Bainbridge.
The other ship, the Marshall Islands-listed Front Altair, was chartered by Taiwanese oil refiner CPC Corp.to carry 75,000 tons of naphtha from the United Arab Emirates to southern Taiwan. The Kokuka Courageous was carrying methanol from Saudi Arabia to Singapore.
An oil tanker is seen after it was attacked at the Gulf of Oman, June 13, 2019.
Why are US-Iran tensions so high?The move was strongly criticised by a number of countries, including the closest allies of the US. More news: Trump Walks Back Comments on Offers of Foreign Dirt amid Bipartisan Criticism
This, of course, doesn't mean that Iran wasn't responsible, and Trump has since come out and asserted that Iran was responsible.