'Spontaneity is not something that protects national security interests, so therefore, when he speaks, when he reacts, he has to make sure he understands that the implications and impact on the United States could be profound,' Brennan said. Photograph: (AFP)
Trump said last week that if the Russian leader 'likes' him it would be an 'asset' to help repair the strained US-Russian relationship
Allegations of Russian interference in US politics cast a shadow over inaugural preparations on Sunday, with the CIA chief warning that President-elect Donald Trump must tamp down his shoot-from-the-hip style to protect national security.
John Brennan's warning to the incoming Republican president - just days before Friday's inauguration - came as senators launched a bipartisan probe into Moscow's alleged meddling in the 2016 election.
"I don't think he has a full appreciation of Russian capabilities, Russia's intentions and actions," Brennan said of Trump on Fox News Sunday.
Trump has been effusive in his praise of Vladimir Putin and said in a news conference last week that if the Russian leader "likes" him it would be an "asset" to help repair the strained US-Russian relationship.
"I think Mr. Trump has to be very disciplined in terms of what it is that he says publicly," Brennan said. "He is going to be, in a few days' time, the most powerful person in the world, in terms of sitting on top of the United States government and I think he has to recognise that his words do have impact."
"This is more than being about him, it's about the United States and national security... he's going to have the opportunity to do something for national security as opposed to talking and tweeting," he said.
"Spontaneity is not something that protects national security interests, so therefore, when he speaks, when he reacts, he has to make sure he understands that the implications and impact on the United States could be profound."
'A sophisticated effort'
US intelligence agencies allege that Putin ordered a covert effort to interfere in the election to boost Trump, 70, and harm his opponent, Democrat Hillary Clinton.
Incoming Vice President Mike Pence on Sunday dismissed notions that the Trump team and the Kremlin had made contact during the 2016 race.
"This is all a distraction," he said on NBC's Meet the Press. "It's all part of a narrative to delegitimize the election and to question the legitimacy of his presidency."
A report from the Director of National Intelligence released this month said hackers working for Russia penetrated Democratic Party computers and accounts to release files embarrassing to Clinton, and also conducted a campaign of media manipulation with the same aim.
Asked whether she believed Russian efforts impacted the election's outcome, Democrat Dianne Feinstein of California -- vice chair of the Senate committee launching the bipartisan probe into the matter -- told NBC "that's what I believe."
"I have had all of the major classified briefings. I have been astonished at what has been a two-year effort at Russia to spearfish, to hack, to provide disinformation, propaganda, wherever it really could," the senator said.
"I think it has been a very sophisticated effort."
Speculation was also swirling around an unproven dossier compiled by a former British MI6 intelligence agent, which alleged close ties between the Trump campaign and the Russian government, and also said Moscow had compromising video of Trump.
The fact that intelligence agencies had briefed the president-elect on the dossier -- which was later published online by BuzzFeed -- lent the allegations credence, but Brennan said the intelligence community was only "making sure that the president-elect was aware that it was circulating."
"I think there are some very salacious allegations in there -- again, unsubstantiated," he said, adding it was "a responsibility in the minds of the intelligence directors" to inform Trump as well as the Obama White House of the report.
Brennan bristled at Trump's likening of the US intelligence community to Nazi Germany, a comparison the president-elect made last week in a tweet after suggesting it was those agencies that had leaked the report.
"What I do find outrageous is equating the intelligence community with Nazi Germany," the outgoing spy chief said of Trump's outburst. "I do take great umbrage at that."
Speaking earlier Sunday on CBS, Pence blamed the scandal on "media bias."
That some news organizations "actually trafficked in a memo that was produced as opposition research and associated that with intelligence efforts -- I think that could only be attributed to media bias," the vice president-elect said.