The U.S. military announced on Sunday the first American casualties of President Donald Trump's intensifying attack on Iran, as a new poll showed only one in four Americans supported strikes against the Middle Eastern country, Reuters reported. 

As the conflict entered its second day, Trump said 48 Iranian leaders had been killed and that the U.S. military had started sinking Iran's Navy, destroying nine Iranian warships so far and "going after the rest."

U.S. aircraft and warships have struck more than 1,000 Iranian targets since Trump ordered the start to major combat operations on Saturday, the U.S. military said. The strikes include B-2 stealth bombers dropping 2,000-lb bombs on hardened, underground Iranian missile facilities, according to Reuters.