He is taking questions from reporters. Here is a sample of his answers, with some analysis from the BBC`s Laura Trevelyan in Washington.
Mr Obama said it was his expectation by early next year to have reduced the prison population at the camp in Cuba to below 100.
He said he will present a plan to Congress to close it, keeping back the threat of using his executive powers if Congress rejects it.
Mr Obama made it clear that when the general election comes along, he will be a key part of the Democratic campaign.
Obama coalition voters will be an important piece for the Democratic nominee to retain.
President Obama said he is confident the US will defeat IS, and for that to happen, the Syrian civil war needs to end.
"Lawless areas" in the Middle East must be contained so extremists cannot take hold, he said. He did not indicate he would change his approach to fighting IS.
"Clearly, this is not the most important event that is taking place in the White House today. There is a screening of `Star Wars` for Gold Star Families and children coming up," Mr Obama said at the beginning of the press conference. Gold Star Families is an organisation for those who lost family members in the Iraq War.
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