Explosions were reported in the US-allied Gulf states of Kuwait and Bahrain early on Sunday following fresh US strikes on targets in Iran.
Kuwait's military said on X that its air defence systems were intercepting hostile missiles and drones.
Iranian broadcaster Press TV also reported explosions in Bahrain.
"The siren has been sounded.. Citizens and residents are urged to remain calm and head to the nearest safe place," Bahrain's Interior Ministry said on X.
Earlier, the US military said it had carried out additional strikes against targets in Iran. It was the second US attack on Iran since the signing of a framework agreement between the two countries in mid-June.
On Friday, the US said it had carried out airstrikes on Iranian missile and drone storage facilities as well as coastal radar sites in response to a drone attack on a commercial vessel in the Strait of Hormuz on Thursday that Washington blamed on Tehran.
