Barack Obama is not expected to approve imminent air strikes in Iraq, partly because there are few clear targets that could blunt the fast-moving uprising, US officials have said.
They said President Obama had made no final decisions and did not rule out the possibility that air strikes could ultimately be used, particularly if a strong target became available.
But the officials said the strikes were not the immediate focus of the administration's continuing discussions about how to respond to the crumbling security situation in Iraq.
Mr Obama is due to brief congressional leaders on the matter at the White House today.
Beyond air strikes, the US has also been considering the possibility of sending a small contingent of special operations forces to Iraq to help train the country's security forces. Officials have also been looking at ways to boost the intelligence available to Iraqi forces.
More broadly, the Obama administration is also pressing for Iraqi prime minister Nouri Maliki to take steps to make his Shiite-dominated government more inclusive.
Mr Obama said last week that any short-term US military actions in Iraq would not be successful unless they were accompanied by political changes by the government in Baghdad.
Despite those calls, there were ominous signs of open warfare between Shiites and Sunnis, the two main Muslim sects. Nearly four dozen Sunni detainees were gunned down at a jail north of Baghdad, a car bomb struck a Shiite neighbourhood of the capital, and four young Sunnis were found dead.
During the United States' eight-year presence in Iraq, American forces acted as a buffer between the two Islamic sects, albeit with limited success. But US forces fully withdrew at the end of 2011 when Washington and Baghdad could not reach an agreement to extend the American military presence there.
But the Obama administration has been forced to rethink its relationship with Iraq after the al Qaida-inspired group Islamic State of Iraq and the Levant (Isis) quickly took control of key Iraqi cities last week.
Mr Obama has already notified the US Congress that he is sending nearly 300 troops in and around Iraq to secure the US embassy in Baghdad and other American assets.