Air strikes resumed between the US and Iran over the weekend as each side claimed to have hit military targets near the Strait of Hormuz.
The US Central Command (Centcom) said it conducted "self-defense strikes on Iranian radar and command and control sites for drones in Goruk, Iran and Qeshm Island this weekend".
Meanwhile, Iran's Islamic Revolutionary Guard Corps (IRGC) said it had targeted an air base used by US forces in retaliation, but did not say where.
Earlier US media reported President Donald Trump had requested "edits" to the latest terms of a proposal that could lead to a peace deal, and there was no sign of a breakthrough.
The US said its strikes on Saturday and Sunday were in response to "aggressive Iranian actions that included the shootdown of a U.S. MQ-1 drone that was operating over international waters".
In a post on X, Centcom said US fighters struck the Iranian military's air defences, a ground control station and two drones that it said "posed a clear threat to ships transiting through regional waters". No American servicemen or women were injured in the attacks, the military said.
The IRGC said it struck the airbase which the US had used to carry out the strikes on its communications tower on Sirri Island in the Gulf, around 40 miles (65km) from Iran's southern coastline.
Iran's military added that its response would be "completely different" if US aggression was "repeated", according to IRGC remarks reported by Iran's semi-official Fars news agency.
Kuwait's military said it was "confronting hostile missile and drone attacks" using its air-defence systems, but did not specify where the interceptions were occurring.
Tehran targeted an air base in Kuwait last week in response to earlier US air strikes, which it said were conducted to prevent Iranian boats and missile strikes from laying mines around the shipping channel.
While a ceasefire came into effect on on 8 April, Donald Trump has repeatedly suggested that the US and Iran were close to a permanent deal and that negotiations were progressing, but so far no formal agreement has been reached.
The latest iteration of the deal included a 60-day cessation of violence, a call to reopen the Strait of Hormuz and a framework to reopen negotiations on Iran's nuclear program, according to the BBC's US partner CBS News.
Approximately one-fifth of global oil and liquefied natural gas (LNG) shipments usually pass through the Gulf shipping channel, with the de facto trade embargo placing upward pressure on fuel prices around the world.
On Sunday, Trump requested changes to an existing deal , which Iran dismissed as "speculation".
