US President Barack Obama said today there was still time to resolve the Iranian nuclear standoff through diplomacy, but that the window for such a solution was closing.
Mr Obama reiterated his position on the Iran nuclear issue after talks with Turkish Prime Minister Tayyip Erdogan on the eve of a nuclear security summit in Seoul.
"I believe there is a window of time to solve this diplomatically but that window is closing," Mr Obama told reporters.
He has pressed Israel to hold off on any attack on Iran's nuclear sites to give sanctions and diplomacy time to work. But he has said military action remains an option if all else fails.
Mr Obama had earlier visited South Korea's tense border with the North.
He flew by helicopter to a US base on the edge of the Demilitarized Zone (DMZ) to meet troops stationed there and get a first-hand look at one of the world's most heavily fortified frontiers.
His tour came amid rising concern over a planned North Korean rocket launch next month that threatens to derail a deal to resume US food aid.
Washington has condemned North Korea's rocket launch plan as a violation of its promise to halt long-range missile launches, nuclear tests and uranium enrichment.
Mr Obama plans to lobby the leaders of China and Russia at the Seoul summit to increase pressure on Pyongyang.
But North Korea's defiance is clouding Mr Obama's much-touted nuclear disarmament agenda, which is also being challenged by Iran's continued nuclear developments in the face of sanctions and international criticism.
Mr Obama will join more than 50 other world leaders tomorrow for a follow-up to the inaugural nuclear security summit he organised in Washington in 2010 to help combat the threat of nuclear terrorism.
While North Korea and Iran are not on the guest list or the official agenda, they are expected to be the main focus of Mr Obama's array of bilateral meetings on the sidelines of the two-day summit.
