TOKYO - A team of UN nuclear watchdog officials visiting North Korea headed on Thursday for the Yongbyon nuclear plant that Pyongyang has promised to mothball as part of an aid-for-disarmament deal, Kyodo news agency reported.

Olli Heinonen (L), chief nuclear inspector for the International Atomic Energy Agency (IAEA), is welcomed by North Korea's General Department of Atomic Energy Director General Ri Je-son (R) upon Heinonen's arrival at Pyongyang airport in Pyongyang June 26, 2007. [Reuters]

The visit to the reactor is the first by International Atomic Energy Agency (IAEA) officials since Pyongyang expelled the Vienna-based agency's inspectors in December 2002.

North Korea subsequently walked out of the nuclear Non-Proliferation Treaty, announced in 2005 that it had atomic bombs and last year conducted its first nuclear test.

A diplomat close to the IAEA said on Wednesday that if the IAEA team, lead by nuclear safeguards director Olli Heinonen, finalised terms for an inspector mission, the agency's 35-nation board of governors would hold a one-day special meeting - probably on July 9 - to ratify the deal.

Inspectors would then be deployed immediately to North Korea.

North Korea's nuclear programme, which dates back to at least the 1980s, is centred at Yongbyon, about 100 km (60 miles) north of Pyongyang. 

The six-country disarmament deal, under which Pyongyang would receive energy aid, security guarantees and better diplomatic standing in return for disabling its nuclear  programmes, was stalled for weeks by a dispute over some $25 million in North Korean funds frozen in a Macau bank at Washington's behest.

Following a surprise visit to Pyongyang by top US nuclear envoy Christopher Hill and the release of the funds, North Korea agreed this week to implement the deal.