A U.S. military image released by the Pentagon in Washington on June 17, which is says was taken from a U.S. Navy MH-60R helicopter in the Gulf of Oman in waters between Gulf Arab states and Iran on June 13, shows personnel that the Pentagon says are members of the Islamic Revolutionary Guard Corps Navy removing an unexploded limpet mine from the M/T Kokuka Courageous, a Japanese owned commercial motor tanker. Picture taken June 13, 2019. U.S. Navy/Handout via REUTERS.

A U.S. military image released by the Pentagon in Washington on June 17 shows what the Navy says is the hull penetration and blast damage on the starboard side of the Japanese owned motor tanker vessel Kokuka Courageous, which was sustained from a June 13 limpet mine attack while operating in the Gulf of Oman and photographed by the U.S. military the following day on June 14, 2019. Picture taken June 14, 2019. U.S. Navy/Handout via REUTERS.

A U.S. military image released by the Pentagon in Washington on June 17, which is says was taken from a U.S. Navy MH-60R helicopter in the Gulf of Oman in waters between Gulf Arab states and Iran on June 13, shows mine blast damage to M/T Kokuka Courageous, a Japanese owned commercial motor tanker. Picture taken June 13, 2019. U.S. Navy/Handout via REUTERS.

Japanese-owned Kokuka Courageous tanker is anchored offshore of the port of Fujairah in a satellite overview image over the United Arab Emirates, June 17, 2019. Courtesy Satellite image ©2019 Maxar Technologies/Handout via REUTERS .

A U.S. military image released by the Pentagon in Washington on June 17 shows what the Navy says is the aluminum and green composite material left behind following the removal of an unexploded limpet mine used in a June 13 attack on the Japanese owned motor tanker Kokuka Courageous in the Gulf of Oman, photographed by the U.S. military the following day on June 14, 2019. Picture taken June 14, 2019. U.S. Navy/Handout via REUTERS.

A U.S. military image released by the Pentagon in Washington on June 17, which the Pentagon says was taken from a U.S. Navy MH-60R helicopter, shows what the Navy says are the remnants of the magnetic attachment device of an unexploded limpet mine on the side of the Japanese owned motor tanker Kokuka Courageous in the Gulf of Oman on June 13, 2019. Picture taken June 13, 2019. U.S. Navy/Handout via REUTERS.

Norwegian-owned Front Altair tanker is anchored offshore of the port of Fujairah in a satellite overview image over the United Arab Emirates, June 17, 2019. Courtesy Satellite image ©2019 Maxar Technologies/Handout via REUTERS.

A U.S. military image released by the Pentagon in Washington on June 17, which is says was taken from a U.S. Navy MH-60R helicopter in the Gulf of Oman, shows personnel that the Pentagon says are members of the Islamic Revolutionary Guard Corps Navy removing an unexploded limpet mine from the vessel M/T Kokuka Courageous, a Japanese owned commercial motor tanker, after another mine exploded on the side of the ship, June 13, 2019. Picture taken June 13, 2019. U.S. Navy/Handout via REUTERS.

A U.S. military image released by the Pentagon in Washington on June 17, shows what the Pentagon says are members of the Islamic Revolutionary Guard Corps Navy photographed from a U.S. Navy MH-60R helicopter after removing an unexploded limpet mine from the M/T Kokuka Courageous, a Japanese owned commercial motor tanker, after it was attacked with another mine which did explode on June 13, 2019. Picture taken June 13, 2019. U.S. Navy/Handout via REUTERS.

A U.S. military image released by the Pentagon in Washington on June 17, which is says was taken from a U.S. Navy MH-60R helicopter in the Gulf of Oman in waters between Gulf Arab states and Iran on June 13, shows personnel that the Pentagon says are members of the Islamic Revolutionary Guard Corps Navy leaving after removing an unexploded limpet mine from the M/T Kokuka Courageous, a Japanese owned commercial motor tanker. Picture taken June 13, 2019. U.S. Navy/Handout via REUTERS.

Norwegian-owned Front Altair tanker is anchored offshore of the port of Fujairah in a satellite overview image over the United Arab Emirates, June 17, 2019. Courtesy Satellite image ©2019 Maxar Technologies/Handout via REUTERS

A U.S. military image released by the Pentagon in Washington on June 17, shows what the Pentagon says is a handprint from an individual who removed an unexploded limpet mine from the side of the motor vessel M/T Kokuka Courageous, a Japanese owned commercial motor tanker after it was attacked with another mine which did explode on June 13, 2019. Picture taken June 14, 2019. U.S. Navy/Handout via REUTERS

A U.S. military image released by the Pentagon in Washington on June 17 shows what the Pentagon says is a view of internal hull penetration and blast damage sustained from a limpet mine attack on the starboard side of the Japanese owned motor tanker Kokuka Courageous in the Guld of Oman in the waters between Iran and Guld States on June 13, 2019. Picture taken June 14, 2019. U.S. Navy/Handout via REUTERS .

A U.S. military image released by the Pentagon in Washington on June 17 shows what the Navy says is hull penetration and blast damage on the starboard side of the Japanese owned motor tanker vessel Kokuka Courageous, which was sustained from a June 13 limpet mine attack while operating in the Gulf of Oman and photographed by the U.S. military the following day on June 14, 2019. Picture taken June 14, 2019. U.S. Navy/Handout via REUTERS.

A U.S. military image released by the Pentagon in Washington on June 17 shows what the Navy says is the aluminum and green composite material left behind following the removal of an unexploded limpet mine used in a June 13 attack on the Japanese owned motor tanker Kokuka Courageous in the Gulf of Oman, photographed by the U.S. military the following day on June 14, 2019. Picture taken June 14, 2019. U.S. Navy/Handout via REUTERS.