"There are certain elements of his temperament that will not serve him well unless he corrects them," he said
US President Barack Obama said he has concerns about Donald Trump's presidency during his first press conference since meeting the President-elect.
Mr Obama told Mr Trump he must reach out to voters who did not support him, while Mr Trump told the outgoing president he was committed to NATO during their one-on-one meeting earlier this week.
“In my conversations with the President-elect, he expressed a great interest in maintaining our core strategic relationships,” Obama said, adding that he had a message from Trump to pass on to world leaders he will meet this week. “One of the messages I will be able to deliver is his commitment to NATO and the transatlantic alliance.”
He said he offered Mr Trump "honest advice" and highlighted the importance of finding trusted aides for the White House. Mr Trump needed to be given the "rope and space" for a "reset", he said, reflecting on his own arrival in the White House during the economic crisis.
He said Mr Trump will have more "time and space" than he had to make "judicious decisions."
He told journalists he thinks Mr Trump will try to "send some signals of unity" to people alienated by what was a ferocious campaign.
He urged the President-elect "to reach out to minority groups or women or others that were concerned about the tenor of the campaign".
When asked about Mr Trump's temperament, he said there will be "certain elements" of his temperament that will not serve him well in office "unless he corrects them". During the campaign, he said Mr Trump was temperamentally unfit to be president.
However, he promised that he and his team will do all they can to help make the transition smooth.
Discussing his own administration, Mr Obama said he's "very proud" that it will end without "significant scandal". however he expressed his own disappointing over not closing Guantanamo Bay.