A series of Iranian strikes on US military bases in Jordan damaged a significant number of Black Hawk helicopters, according to The New York Times.

Citing sources, the newspaper reported that Iran had attacked American military facilities in the kingdom four times over the past five days. One of the strikes hit a base in eastern Jordan where the helicopters were stationed. Each Black Hawk was valued at $21 million.

During Friday’s attack on Muwaffaq Salti Air Base in Azraq, two US servicemen were killed, another was reported missing, and dozens of soldiers were wounded. The Pentagon declined to comment publicly on the extent of the damage.

The exchange of strikes between Iran and the United States in the Middle East has continued since early June. After US attacks on Iranian facilities, Tehran began launching retaliatory strikes on American bases across the region. Military sites in Jordan, Kuwait, Bahrain and Qatar have repeatedly come under attack.

On June 10, the Islamic Revolutionary Guard Corps said it had struck four targets, including F-35 hangars at the US Al-Azraq Air Base in Jordan. Iran said ballistic missiles were used in the attack. Tehran later reported additional strikes on the same base.