Two tankers caught fire in the Gulf of Oman on Thursday, forcing the crews of the Norwegian-owned Front Altair and the Japanese-owned Kokuka Courageous to abandon the vessels.
Though it remains unclear what caused the fires, the US blamed Iran on Thursday for the incident.
Iran has denied the accusations.
The attacks occurred during Japan’s Prime Minister Shinzo Abe visit to Iran, aimed at de-escalating tensions between the US and Iran, and preventing an “accidental conflict”.
“Japan adamantly condemns the act that threatened a Japanese ship, no matter who attacked”, Abe told reporters on Friday.
The PM pledged to help ease tensions in the region and called on “all related countries” to avoid actions that could inflate tensions further.
Japanese Industry Minister Hiroshige Seko said on Friday that Japan is investigating the incident.
The EU also called for both the US and Iran to exercise “maximum restraint”.
“We have said repeatedly that the region doesn’t need further escalation, it doesn’t need destabilization, it doesn’t need further tension, and therefore we call for maximum restraint to avoid provocations”, a spokesperson for the EU’s foreign service told reporters.
The spokesperson said the EU Foreign Service were “gathering more information” and “assessing the situation”.
China echoed the call for both sides to remain calm, saying no one wants to see war in the Gulf.
“We hope all relevant parties remain calm and exercise restraint and avoid tensions further escalating, and hope all sides can jointly safeguard navigational safety in the relevant waters and regional peace and stability”, China’s Foreign Ministry spokesperson, Geng Shuang, said Friday.
China is the largest buyer of Iranian oil and continues to support the Iran nuclear deal.
The UK however, took a more clear-cut stance, in favour of the US.
British Foreign Secretary Jeremy Hunt said that the UK would make its own assessment, but that it was working on the basis that US allegations were right.
Hunt said he has been in contact with US Secretary of State Mike Pompeo and that “while [the UK] will be making [its] own assessment soberly and carefully, our starting point is obviously to believe our US allies”.
If Iran is involved it is a “deeply unwise escalation”, the Foreign Secretary added.
"The United States assesses that Iran is responsible for these attacks. No proxy group in the area has the resources or skill to act with this level of sophistication. Iran however, has the weapons, the expertise and the requisite intelligence information to pull this off," Jonathan Cohen, the US Acting Permanent Representative to the UN, said on Thursday.
“Iran categorically rejects the US unfounded claim with regard to 12 June oil tanker incidents, and condemns it in the strongest possible terms”, said a statement from the Iranian mission to the United Nations released on Friday.
In a similar incident on May 12, four vessels including two Saudi oil tankers were damaged in incidents which were described as “sabotage attacks.” US National Security Advisor John Bolton has alleged Iran was behind those attacks.
