Iran said Thursday that it had targeted a U.S. air base in response to new U.S. military attacks in the south of the country, raising new doubts about a deal to end the war and reopen the crucial Strait of Hormuz.

Axar.az informs, citing NBC, the exchange, which appeared to draw in U.S. ally Kuwait, was the second military clash in days and the most significant since the ceasefire between Washington and Tehran came into effect last month.

The new military clash began Wednesday when the U.S. shot down four Iranian one-way attack drones and struck a ground control station inside Iran that the military assessed as presenting a direct threat to U.S. forces and commercial shipping, a U.S. official said.

The strikes took place in the vicinity of Bandar Abbas, a port city near the Strait of Hormuz, both the U.S. official and Iranian media reported. Several American ships had attempted to pass through the strait without authorization, Iranian news agencies reported.

It was the second time in three days the U.S. has carried out what it described as defensive strikes against Iran.