Joe Biden: Intelligence officials told us Trump allegations might leak

US vice president Joe Biden has said top intelligence leaders told him and President Barack Obama about unsubstantiated claims about Donald Trump because they were concerned the information might become public.

Mr Biden said he and Mr Obama were initially surprised that intelligence officials felt the need to brief them on unverified claims that Russia had compromising information about President-elect Trump.

The vice president said: "It's something that obviously the agency thinks they have to track down."

Mr Biden did not specify which agency, but said later that he was surprised the allegations "made it to the point where the agency, the FBI thought they had to pursue it".

The vice president said neither he nor Mr Obama asked for more details.

He said the intelligence community could not say whether the information was true.