Last Updated: Monday, 9 October 2006, 02:10 GMT 03:10 UK
Japan-China summit warns N Korea
Shared alarm over N Korea's threat may be fuelling improved ties
The leaders of China and Japan have both said that a nuclear test by North Korea would be "unacceptable".
The statement came after Japan's new Prime Minister Shinzo Abe met Chinese leaders in their capital Beijing - the first such contact in five years.
North Korea's threat last week to test a nuclear weapon may have given greater urgency to improved relations between the two countries, correspondents say.
Last Updated: Monday, 9 October 2006, 03:09 GMT 04:09 UK
Reports from North and South Korea say the communist authorities in North Korea have carried out their first ever test of a nuclear weapon.
The North Korean state news agency said the underground test was a success.
In South Korea, President Roh Moo-hyun convened a meeting of his top security officials following the reports.