VIENNA - THE world's top nuclear watchdog chose Japan's Yukiya Amano as its next head on Thursday - and he touched on the devastation US atom bombs wreaked on his country in pledging to do his utmost to prevent the spread of nuclear arms.

The decision by the 35-nation International Atomic Energy Agency board ended a tug of war on who should succeed Nobel Peace laureate Mohamed ElBaradei, who saw his agency vaulted into prominence during a high-profile 12-year tenure.

North Korea left the nonproliferation fold to develop a nuclear weapons program on Mr ElBaradei's watch and his agency later launched inconclusive probes on suspicions that those to nations were interested in developing nuclear weapons.

Mr ElBaradei's activist approach to his job often rankled with Washington - and it had a strong preference for Mr Amano, seen by the US as a technocrat amenable to pursuing a hard line on Iran's nuclear ambitions.

Mr Amano's allusions to the bombings of Hiroshima and Nagasaki pointed to a deep commitment to non-proliferation.

And Japan, which is separated from North Korea only by a narrow body of water, keenly shares the United States' concerns about Pyongyang's nuclear program.

Developing countries supported Mr Amano's rival, South Africa's Abdul Samad Minty, considered ready to challenge the US and other nuclear power countries on issues such as disarmament - and which are generally supportive of Iran's claims to having a right to nuclear power.

An initial session in March ended inconclusively and Thursday's meeting went down to the wire, with Amano winning only in the fourth round.

That and the fact that Mr Amano barely eked out his victory, just clearing the two-thirds majority needed, reflected a continuing divide between the two camps.

The divisions have served as an obstacle in one of its key tasks - probing nations suspected of secret, possibly weapons-related, nuclear activities. -- AP