The U.S. military released new images on Monday, which it says showed Iran's Revolutionary Guard Corp (IRGC) removing an unexploded limpet mine from a Japanese-owned tanker that was attacked on June 13 in the Gulf of Oman, as Washington blames Tehran for the attack.

"Iran is responsible for the attack based on video evidence and the resources and proficiency needed to quickly remove the unexploded limpet mine," the U.S. military's Central Command said in a statement explaining the still-images.

Tehran has denied involvement in the June 13 oil tanker attack near the Strait of Hormuz.

The Iranian mission to the United Nations said in a statement on Thursday evening that Iran "categorically rejects the U.S. unfounded claim with regard to 13 June oil tanker incidents and condemns it in the strongest possible terms."

Read more: Iran rejects U.S. blames for tanker attacks in Gulf of Oman

The Norwegian-owned Front Altair and Japanese-owned Kokuka Courageous were attacked on June 13 in waters between the Gulf Arab states and Iran, in which both tankers experienced explosions and crews were forced to abandon the ships and leave the vessels adrift in the Gulf of Omen.

The crews of both ships struck on Thursday were picked up safely. The Bahrain-based U.S. Navy Fifth Fleet said it had assisted the two tankers after receiving distress calls.

One source said the blast on the Front Altair, which caught fire and sent a huge plume of smoke into the air, may have been caused by a magnetic mine. The firm that chartered the Kokuka Courageous tanker said it was hit by a suspected torpedo, but a person with knowledge of the matter said torpedoes were not used.