Air raid sirens echoed across Bahrain for the third time on Thursday, followed by explosions, as Iran intensified its retaliation against US airstrikes, claiming drone attacks on American military sites in Bahrain, Kuwait and Qatar. Bahrain's Interior Ministry urged residents to seek shelter as tensions across the Gulf escalated.The fresh alert came hours after Iran claimed it had launched one-way attack drones at US military sites in Kuwait, Qatar and Bahrain in retaliation for the American strikes earlier in the day.According to Iranian state media, the Iranian military said it targeted a U.S. Patriot missile interceptor system in Kuwait, an early warning system in Qatar, and fuel storage facilities used by the US Army in Bahrain. In a separate claim, Iran's army said it had struck Patriot air defence systems in Kuwait, a satellite antenna in Qatar and a U.S. Army fuel storage facility in Bahrain using a large number of attack drones.Read More: Iran War Runtime: A day or two, a week, or a month? White House official says thisThe developments mark a further escalation in the regional conflict, with Bahrain, Kuwait and Qatar all reporting attacks or military activity linked to Iran's retaliation following the US airstrikes.Iran rejects US pressureIran on Thursday said it would not allow what it described as US "deal breaches, bullying and baseness" to undermine its national interests, while condemning American strikes on its southern coastal provinces and two bridges in eastern Iran. The Iranian Foreign Ministry called the attacks on civilian infrastructure a "gross war crime."