Members of Donald Trump's presidential campaign had repeated contacts with senior Russian intelligence officials in the year before the election, it has been reported, as pressure grows on the president to explain his relationship with Moscow.

American law enforcement and intelligence agencies discovered the alleged communications in phone records and intercepted calls around the same time they uncovered evidence that Russia was trying to interfere with the US election by hacking into the Democratic National Committee, current and former American officials told The New York Times.

The officials said there was no evidence the Trump campaign was colluding with the Russians on the hacking or other efforts to disrupt the election, the newspaper reported.