US forces carried out strikes against Iran on Tuesday in what President Donald Trump said was retaliation for the downing of an American helicopter a day earlier by the Islamic Republic.Trump, in a telephone interview with ABC News, said the United States was responding "in a strong manner" to "what they did with our helicopter last night.""And I believe the response should be very strong, very powerful, and that's what this one is," he said.US Central Command (CENTCOM) said American forces "began launching self-defense strikes against Iran, at 5 pm ET (2100 GMT) today at the Commander in Chief's direction" and "the mission is a proportional response to unjustified Iranian aggression."Iranian media reported that explosions were heard on Iran's southern coast near the Strait of Hormuz.The US strikes came just hours after Trump had said negotiations to end the Middle East war were in their final stages -- a claim he has made repeatedly in the past few weeks.A shaky ceasefire between the warring parties has been in place since April 8, but it faced a major test when Iran and Israel renewed attacks over the weekend, before each side announced a halt.Israeli attacks on Lebanon continued, however, and Lebanese officials said 11 people were killed in airstrikes on Tuesday on the historic city of Tyre in the south of the country.The Israeli military also warned the entire city to evacuate.