'It's a bad idea': CNN commentator says Trump should stop questioning US intelligence agencies

Donald Trump's tweets questioning the US intelligence community's handling of the Russian cyberattack investigation prompted a warning from a CNN commentator on Tuesday night.

Timothy Naftali, a presidential historian for the network, said the president-elect should not try to cast doubt on the nation's top spy agencies.

"It's a bad idea," Naftali said, "the intelligence community has information about him that I'm sure he would like not to be released."

Naftali stopped short of implying there's a big secret about the incoming president, but said "it doesn't make sense for Trump to be making adversaries in the intelligence community ... a community that serves presidents regardless of party."

He suggested Trump should "stay silent" about the Russian hacking investigation.

Trump tweeted earlier on Tuesday night: "The 'Intelligence' briefing on so-called 'Russian hacking' was delayed until Friday, perhaps more time needed to build a case. Very strange!"

Unnamed US officials cited by NBC News and USA Today said the meeting between Trump and the heads of US intelligence agencies had already been on the books for Friday.