By Charles Scanlon
BBC News, Seoul
The leaders of China and South Korea have expressed deep concern about the deadlock over North Korea's nuclear weapons programme.
The IAEA has said North Korea may have six nuclear weapons
They called on the North to return immediately to six party talks which have been stalled since last June.
North Korea said it wanted to clarify the United States position before making a final decision on talks.
An escalation in the war of words between North Korea and the United States has alarmed the region.
Indications that the North may be preparing to test an atomic bomb or increase its nuclear arsenal have added to the sense of crisis.
At a meeting in Moscow, presidents Hu Jintao and Roh Moo-hyun urged North Korea to return immediately to talks which have been stalled since last summer.
In a glimmer of hope, North Korea's foreign ministry said it still wanted a negotiated solution, and had requested a meeting to confirm recent statements from Washington.
These include an offer of bilateral contacts within the framework of six party talks, a long-standing North Korean demand.
That may have been intended as an olive branch, but US officials have also hinted at more coercive action, with references in recent days to Washington's military power in the region.
Pyongyang radio replied that the North was also capable of a pre-emptive strike.
The head of the International Atomic Energy Agency, Mohammed ElBaradei, said on Sunday that North Korea may already have six nuclear weapons.
The North declared itself a nuclear state last February and says it wants to be treated as an equal partner by the United States.