Later in the news conference, Obama addressed concerns about the influence that Russia may have on the U.S., criticizing the country in the process.
"They are a smaller country, they are a weaker country, their economy doesn't produce anything that people want to buy except for oil and gas and arms. They don't innovate. But they can impact us if we lose track of who we are," he said.
"Mr. Putin can weaken us just like he's trying to weaken Europe if we start buying into notions that it's OK to intimidate the press or lock up dissidents or discriminate against people because of their faith or what they look like."
"What is it about our political system that made us vulnerable to these kinds of potential manipulations which, as I've said publicly before, were not particularly sophisticated. This was not some elaborate complicated espionage scheme. They hacked into some Democratic Party emails that contained pretty routine stuff, some of it embarrassing or uncomfortable," he said.
He warned that if the U.S. continues to be targeted, it can respond.
"Our goal continues to be to send a clear message to Russia or others not to do this to us because we can do stuff to you. But it is also important for us to do that in a thoughtful methodical way. Some of it we do publicly. Some of it we will do in a way that they know but not everybody will," he said.
While he said that he was going to refrain from commenting in detail about the election, he did say that "I don't think [Hillary Clinton] was treated fairly during the election ... the coverage of her and the issues was troubling."
Obama made a few comments about his communication with Trump, saying that the last time they spoke was a "few days" ago on "a whole range of transition issues." Obama characterized their conversations as cordial, and said that he has been "making some pretty specific suggestions about how to ensure that regardless of disagreements about policy, maybe I can transmit some thoughts about maintaining the effectiveness, integrity, cohesion of the office, our various democratic institutions."
"He's listened. I can't say that he will end up implementing but the conversations themselves have been cordial as opposed to defensive in any way," Obama said.
Obama also spoke about the validity of the election, and said that "there was not the kind of tampering with the voting process that was a concern, and will continue to be a concern going forward."
"The votes that were cast were counted, they were counted appropriately, we have not seen evidence of machines being tampered with," he said.
The president started by listing his accomplishments from his eight years in office, and said that the country is in a state that he is "proud to leave to my successor," without specifically naming Trump.
"I think people will be able to compare and contrast and make judgments about what worked for the American people, and I hope that building off the progress we've made, that what the president-elect is proposing works," he said later. "What I can say with confidence is that what we've done works. That I can prove."