The US military carried out new strikes in Iran on Wednesday, targeting a site around the Strait of Hormuz that posed a threat to US forces and commercial traffic, according to a US official.

The US also shot down four Iranian attack drones that posed a threat, the official said.

US forces struck an Iranian ground control station in Bandar Abbas that was about to launch a fifth drone. These actions were measured, purely defensive and intended to maintain the ceasefire, they added.

Earlier, three explosions were heard to the east of Bandar Abbas, a strategic Iranian port city and naval base near the Strait of Hormuz, Iran’s semi-official Fars News Agency reported in the early hours of Thursday.

The blasts were reported at around 1:30 a.m. local time and caused the air defence systems of Bandar Abbas to be briefly activated, according to Fars, a media outlet with links to Iran’s Islamic Revolutionary Guard Corps (IRGC).

“The exact location and source of these sounds are still unknown, and follow-ups are continuing to determine them,” Fars reported.