Japan and South Korea urged North Korea on Wednesday to refrain from any new "provocations", amid concern the secretive Asian state will soon conduct a new nuclear test.
North Korea, which tested plutonium devices in 2006 and 2009, has almost completed preparations for a third nuclear test, a senior source with close ties to Pyongyang and Beijing told Reuters last month.
"Japan strongly urges (North Korea) not to conduct any further provocation including nuclear tests or further (missile)launches," Kazuyuki Hamada, Japanese parliamentary vice-minister for foreign affairs, told a nuclear meeting in Vienna.
The isolated state sacrificed the chance of closer ties with the United States after it tried to test-launch a long-range rocket on April 13 and was censured by the U.N. Security Council, which includes the North's sole major ally, China.
Hamada said last month's launch - which ultimately failed - was "intolerable" to Japan.
The South Korean representative at the two-week meeting in Vienna to discuss the nuclear Non-Proliferation Treaty (NPT), from which North Korea withdrew in 2003, also used the opportunity to urge restraint.
North Korea "should realize that further provocations will only exacerbate its isolation," said Kim Bong-hyun, deputy minister for multilateral and global affairs at the Ministry of Foreign Affairs and Trade.
The North has long argued that in the face of a hostile United States, which has military bases in South Korea and Japan, it needs a nuclear arsenal to defend itself.
Six-party aid-for-disarmament talks involving the two Koreas, the United States, Japan, Russia, and China, have been stalled since 2008 when the North walked away from the deal.
(Reporting by Fredrik Dahl; Editing by Myra MacDonald)