President Barack Obama and the Republican presidential candidates clashed Tuesday over how to deal with Iran's nuclear programme.
The Republican contenders accused Obama of weakness, while Obama blasted back that presidents do not launch wars lightly.
The debate over an Iran strategy occurred as Israeli Prime Minister Benjamin Netanyahu was finishing a visit to Washington. It also coincided with Iran agreeing to allow nuclear inspectors to return to its nuclear facilities and the US and other world powers offering a restart in nuclear negotiations with Tehran.
"We have a window of opportunity where this can still be resolved diplomatically,'' Obama told his first news conference of the year.
"We are going to continue to apply pressure even as we provide a door for the Iranian regime to walk through where they can rejoin the community of nations.''
Obama spoke after Republicans Mitt Romney, Rick Santorum and Newt Gingrich each presented themselves as hawkish alternatives to the president, unafraid of the consequences of military conflict.
The candidates paused while competing for votes in the high-stakes Super Tuesday primaries to join the speakers' lineup at a conference of America's leading pro-Israel lobby. Santorum appeared in person, while Romney and Gingrich spoke via satellite.
All spoke of the need for even tougher sanctions or military action against Iran.