President Obama said more investigation is required to determine who used chemical weapons in Syria and he would not commit to engaging in military action if it turns out to be the Syrian government.
The U.S. government determined last week that such weapons had been used. And President Obama had said that their use by Syrian President Bashar al Assad would constitute crossing a "red Line" and fundamentally change U.S. involvement in the ongoing civil war there.
But at his first press conference since the U.S. determined chemical weapons have been used, President Obama said it is not entirely clear who used the weapons. He cautioned that the U.S. would be "prudent" in moving forward.
The president would not commit to U.S. military intervention if it is determined that the Syrian government did use chemical weapons against rebels in their own country. Some on Capitol Hill from both parties have endorsed such a tactic.
Obama said only that the U.S. would "rethink the range of options" against Syria.
President Obama also answered questions on the Boston terror attack, where he said it appears to him that the FBI acted appropriately in chasing down leads from the Russian government about suspected bomber Tamerlan Tsarnaev.
He dismissed a question from ABC's Jonathan Karl about whether he's stll "got the juice" to enact his domestic agenda, including immigration reform and passing a deficit reduction passage.
And he defended the implementation of Obamacare, the signature legislative accomplishment of his presidency. Even some Democrats have said that implementing the rest of the law – the bulk of insurance requirements go into effect Jan. 1, 2014 – is troubled.
Obama said most of the law has already been implemented and is working just fine.
"Despite all the hue and cry and sky is falling predictions about this stuff, if you've already got health insurance, the part of Obamacare that affects you is already in place," he said, speaking into the camera to Americans watching on TV.
That's about 85 percent of the country, he said, although he later admitted that "even if we do this perfectly, there will be glitches and bumps."
Check back here for more on the press conference later.
White House Press Secretary Jay Carney announced the news conference on Twitter with a reference to the president's comedy routine at the White House Correspondents' Association dinner Saturday.
"POTUS brought down the house on Sat night at #WHCD - but he didn't take questions. So, today he will. 10:15am in Brady Briefing Room."
President Obama opened the press conference with a reference to a complaint by one journalist at that dinner that he doesn't take enough questions.