The shaky ceasefire between the United States and Iran has been tested further, with American forces targeting Iranian drones and radar sites and Iran firing ballistic missiles at US bases in the Gulf, BBC News reported.

The US military said its strikes were a response to four Iranian "one-way attack drones" launched toward the Strait of Hormuz, which it said "posed an immediate threat to regional maritime traffic." All four drones were shot down, US Central Command (Centcom) said.

Iran retaliated by firing ballistic missiles at two US air bases in Kuwait and at US Navy facilities in Bahrain, according to Iran's Irib news agency. Bahrain and Kuwait both condemned the attacks, saying the drone and missile fire had been successfully repelled. The United Arab Emirates and Qatar also denounced the Iranian strikes on their Gulf neighbours. Centcom said initial assessments showed that of the seven Iranian missiles fired at the two Gulf states, six were intercepted and one failed to reach its target.

Iran's foreign ministry said the US strikes on radar installations in Sirik and at Qeshm island were a "flagrant" violation of the ceasefire and "an attack on the national sovereignty and territorial integrity of the Islamic Republic of Iran." The statement added that the strikes demonstrated "complete disregard for the principles of international law and the United Nations Charter." Iran's Islamic Revolution Guard Corps (IRGC) said it had hit "enemy bases" in retaliation.

The exchange comes as ceasefire negotiations have stalled, with US media reporting that President Donald Trump had requested changes to the terms of an agreement. An Iranian foreign-ministry spokesman said the US was "constantly changing its views and putting forward new or contradictory demands."

The US and Israel launched wide-ranging strikes on Iran on 28 February, sparking conflict across the Middle East. Iran responded by attacking Israel and US-allied Gulf states and effectively closing the Strait of Hormuz, through which roughly 20% of the world's oil and liquefied natural gas travels — sending prices sharply higher. Shortly after a ceasefire was agreed in early April, the US established a blockade of Iranian ports, which Trump said would remain "in full force and effect until an agreement is reached, certified, and signed."