Washington: US President Donald Trump insisted on Tuesday that he had the right to share “facts” with Russia, one day after explosive allegations emerged that he divulged highly-classified intelligence to Russian diplomats in the Oval Office.

According to a report from the Washington Post, Mr Trump revealed highly-classified information on the ISIS group during a meeting last week with Russian foreign minister Sergei Lavrov and Moscow’s man in Washington Sergey Kislyak.

The information reportedly came from a US ally who had not authorised Washington to share it with Moscow, a potential blow to intelligence relationships based on trust that secrets will be kept.

“As President, I wanted to share with Russia (at an openly scheduled W.H. meeting) which I have the absolute right to do, facts pertaining to terrorism and airline flight safety,” Mr Trump said in an early morning tweet.

Mr Trump wrote that he was motivated by “humanitarian reasons, plus I want Russia to greatly step up their fight against ISIS & terrorism.”

The disclosure did not break the law, according to security blog Lawfare, but such revelations could expose sources and methods, it said.