He said on Twitter that an intelligence briefing he was due to receive on alleged Russian interference in the 2016 election – which is said to have benefited Mr Trump – had been delayed.
It said: “The ‘Intelligence’ briefing on so-called ‘Russian hacking’ was delayed until Friday, perhaps more time needed to build a case. Very strange!”
But US intelligence officials insisted there had been no delay in the briefing schedule.
Several US agencies including the FBI and the CIA believe Russia directed hacks against the Democratic Party and the campaign of its presidential candidate, Hillary Clinton, releasing embarrassing information through WikiLeaks and other outlets to help Mr Trump win the election.
The hacking resulted in Barack Obama expelling 35 Russian diplomats as part of a raft of new sanctions.
“All Americans should be alarmed by Russia’s actions,” Mr Obama said, claiming the extent of data theft and cyber-attacks uncovered “could only have been directed by the highest levels of the Russian government”.