India’s Minister of Ports, Shipping and Waterways, Sarbananda Sonowal, announced on Thursday that the three Indian sailors reported missing after a U.S. strike on an oil tanker in the Gulf of Oman have been confirmed dead.

The United States said its military carried out a “precision strike” against the vessel after it failed to comply with instructions, adding that it was transporting Iranian oil.

Indian sources said New Delhi summoned the deputy chief of the U.S. mission and lodged a strong protest over the attack. Earlier, India’s Ministry of External Affairs had reported that 21 Indian crew members were rescued, while three remained missing before their deaths were confirmed.

The ministry also summoned the U.S. chargé d’affaires to protest the strike on the oil tanker off the coast of Oman and issued a formal condemnation of the attack on the commercial vessel “Citybello.”