The US President is to give a speech tomorrow - in the US the eve of the anniversary of the September 11 attacks - preparing the American public for a campaign against Isis.
US officials said Obama would go on the offensive with a broader counterterror mission than he had previously been willing to embrace.
US Secretary of State John Kerry said nations around the world were seeking to defeat the militants with a coalition "built to endure for the months, and perhaps years, to come".
Officials say the more aggressive posture will target Isis beyond protecting US interests or helping to resolve humanitarian disasters.
Obama will still not commit US troops to a ground war and will rely heavily for now on allies to pitch in.
Diplomatic efforts to gain support were boosted yesterday when Iraq's Parliament voted to approve a new Government aimed at winning broad backing against Isis, with Haider al-Abadi as Prime Minister.
Abadi, a member of Iraq's Shia majority whose candidacy was backed by the US, has promised to include members of the Sunni minority and Kurds in his Government.
The attempt to heal sectarian rifts is seen as vital to undermining Isis' appeal in the Sunni heartlands, where disaffection with the previous Shia-dominated Government assisted the extremist Islamist group in its rise.
The Pentagon said it had "not yet conducted any strikes against targeted individuals", but refused to rule out the possibility that it was using drones for surveillance.
Several residents of Raqqa and Isis jihadists photographed a white drone, saying it flew low over the city for most of Saturday and again on Sunday. Experts said they believed the aircraft was an unarmed MQ1 Predator on a reconnaissance flight.
Killing Baghdadi would be a major coup for Obama, who has been widely criticised for not taking sufficiently tough action against Isis. But the effect of the death of its leader on the group is less certain. Baghdadi is at the apex of an elaborate hierarchy, with a "cabinet" of deputies who manage military operations and domestic governance.
Former CIA counter-terrorism analyst Aki Peritz predicted that Obama would order a strike against Baghdadi if the opportunity arose.
"The US is already exerting lethal force against the Islamic State," he said. "If it had the opportunity to take its top dog off the battlefield, it would pull the trigger." Telegraph Group Ltd, AP