Brussels - The European Union's top diplomat on Monday warned North Korea of possible international sanctions after it confirmed that it had tested a nuclear bomb.

"These irresponsible acts by North Korea warrant a firm response by the international community. The EU will be in contact with its partners to discuss appropriate measures," Javier Solana said in a statement released in the EU's Brussels headquarters.

The action "further threatens regional peace and security in North-East Asia, following (North Korea's) launch of a long-range missile in April this year" and is a "flagrant violation" of UN Security Council resolutions, the statement said.

The EU has long opposed North Korea's nuclear programme, which it sees as a threat to stability in Asia.

However, last week the bloc failed to win Chinese support for its diplomatic push at a summit in Prague.

Ahead of the meeting, the EU had urged China to condemn North Korea's April 5 test-firing of a long-range missile and to demand that Pyongyang rejoin international talks on the nuclear issue.

China rejected that call, instead calling for a statement of "concern over the current situation on the Korean Peninsula." (dpa)