President Donald Trump vetoed an Israeli plan in recent days to kill Iran's Supreme Leader Ayatollah Ali Khamenei, two U.S. officials told Reuters on Sunday.

"Have the Iranians killed an American yet? No. Until they do we're not even talking about going after the political leadership," said one of the sources, a senior U.S. administration official.

The officials, speaking on condition of anonymity, said top U.S. officials have been in constant communications with Israeli officials in the days since Israel launched a massive attack on Iran in a bid to halt its nuclear program, according to Reuters.