The two leaders pledged to work closely to resolve the crisis
The South Korean President, Roh Moo-hyun, and US President George W Bush have warned that they "would not tolerate" nuclear weapons in North Korea.
In a joint statement issued after a summit in Washington, the two presidents said they would work with the international community to achieve a peaceful resolution to the nuclear crisis.
The two leaders emerged from their first ever meeting touting a personal chemistry which correspondents had noted was essential in papering over their differences on how to disarm the rogue state.
Escalatory moves by North Korea will only lead to its
greater isolation and a more desperate situation in the
US-South Korean statement
Mr Roh has stressed that continued engagement with the North is the best way to forge a peaceful solution on the Korean peninsula, whilst Washington has taken a tougher line - reserving the right to push for economic sanctions against the isolated North, or even resort to military action.
Pyongyang said on Thursday that the only way to resolve the
dispute was for the United States to "renounce its hostile
policy" towards the North.
"I assured the president we will continue to work to achieve a peaceful solution," Mr Bush said in a symbolic joint appearance with Mr Roh in the White House Rose Garden after their talks.
But the statement added that "increased threats to peace and stability on the peninsula would require consideration of
further steps". It did not elaborate.
"The president never takes his options off the table in
any circumstance," Bush's national security adviser,
Condoleezza Rice, told reporters later.
The two leaders also discussed the military alliance between the two countries, which has been strained by recent anti-US sentiment in the South over the large number of US troops stationed in the country.
Although Mr Roh came to office promising to work for a more equal relationship with the US, the escalating tensions with North Korea have underscored Seoul's military dependence on Washington.
Any relocation of US troops bordering North Korea from
the front "should be pursued taking careful account of the
political, economic and security situation on the peninsula and in Northeast Asia", the statement said.
North Korea said in a commentary in the state newspaper Rodong Sinmun, just hours after the summit, that the onus was on Washington to resolve the crisis.
"It will be possible to settle the outstanding issues
between the DPRK and the U.S. including the nuclear issue
only if the US opts to renounce its hostile policy toward
the DPRK and approaches dialogue from a proper stand," the report said.
In marked contrast with the frosty relationship between Mr Bush and Mr Roh's predecessor, Kim Dae-jung, both leaders complimented the other on his personal style.
Oct 2002 - US says N Korea "admits" secret nuclear programme
Nov 2002 - US-led decision to halt oil shipments to N Korea
Dec 2002 - N Korea expels two nuclear watchdog's inspectors
Jan 2003 - N Korea says it is withdrawing from Nuclear Non-Proliferation Treaty
Feb 2003 - N Korea "restarts" Yongbyon nuclear plant
Apr 2003 - N Korean and US talks collapse in China
"I have found the president to be an easy man to talk to. He
expresses his opinions very clearly and it's easy to understand," Mr Bush said.
"There's no question in my mind we'll have the kind of personal relationship where we will consult freely to solve major problems," he added.
Mr Roh agreed. "We have come to trust each other
and have confidence in each other," he said.
The crisis on the Korean peninsula has been simmering since last October, when Washington said Pyongyang admitted to a secret nuclear weapons programme.
At a meeting between the US and North Korea aimed at resolving the issue in April, Pyongyang reportedly offered to give up its nuclear programme in exchange for substantial economic and diplomatic concessions.
Washington said it would review the offer. Any decision is likely to be influenced by the US' allies in the region - South Korea, and Japan, whose leader Mr Bush is meeting later this month.