Radioactivity has been detected from a nuclear test by North Korea, said a US government official on Friday.

The official, who spoke on condition of anonymity, said a preliminary US intelligence analysis has shown radioactivity in air samples collected near a suspected nuclear test site of North Korea.

But the Bush government has not made a definitive conclusion about the nature of the blast which North Korea defined as its first nuclear test, he said.

Earlier Friday, the US government said that it still does not have a definite answer on whether North Korea conducted a nuclear test.

Also on Friday, the UN Security Council (UNSC) President for October Japanese UN Ambassador Kenzo Oshima said UNSC is set to vote today on a resolution sponsored by the United States and other nations.

"The relevant provision is going to say measures will be taken in accordance with national legislation and measures consistent with international law," Oshima said.

Council members and experts have held intensive consultations over the past few days on the resolution, which has been amended several times. The five permanent members have been meeting together with Japan.

Oshima noted that although all members strongly condemned North Korea's nuclear test in consultations, a major focus was whether to invoke Chapter 7 of the UN Charter that allows for sanctions and the use of force in the case of a threat to or breach of peace.

UN Secretary-General Kofi Annan stressed the urgent need for North Korea to return to the six-party talks that have been seeking to resolve the issue of its nuclear program.

(Xinhua News Agency October 14, 2006 )