DUBAI, United Arab Emirates (AP) —

The U.S. military offered condolences Thursday to Iran over a friendly fire incident in the Islamic Republic that killed 19 of its troops, identifying the weapon used in the incident as an anti-ship cruise missile.

Iranian authorities on Monday said that a missile struck the Iranian navy vessel Konarak near the port of Jask, some 1,270 kilometers (790 miles) southeast of Tehran in the Gulf of Oman. Authorities said the Konarak was too close to a target and was accidentally hit Sunday in an incident that also wounded 15 troops.

In a statement, Capt. Bill Urban, a spokesman for the U.S. Central Command, said the force offered “our sincere condolences to the Iranian people for the tragic loss of life.” However, Urban also criticized the training for taking place so close to the Strait of Hormuz, the narrow mouth of the Persian Gulf through which 20% of all oil passes.

“While we are troubled that this mishap occurred in such close proximity to a high-traffic international shipping lane and at a time when most of the region’s focus is on the fight against COVID-19, the unnecessary loss of life is regrettable,” he said.

Tensions had been expected to rise after Iran’s government overcame the initial chaos that engulfed its response to the coronavirus pandemic. In April, the U.S. accused Iran of conducting “dangerous and harassing” maneuvers near American warships in the northern Persian Gulf. Iran also had been suspected of briefly seizing a Hong Kong-flagged oil tanker just before that.

President Donald Trump withdrew the U.S. from Tehran’s nuclear deal with world powers two years ago, launching a maximum pressure campaign against Iran that has repeatedly pushed the arch-rivals to the verge of conflict.

Analysts have warned regional tensions will likely increase again. This week also marks the year anniversary of attacks on oil tankers near the strait that the U.S. blamed on Iran.