The White House today said a nuclear test by the Democratic People's Republic of Korea (DPRK) would be "a provocative act" and expected the UN Security Council to take immediate action on the issue.

A DPRK nuclear test "would constitute a provocative act, in defiance of the will of the international community and of our call to refrain from actions that would aggravate tensions in North East Asia. We expect the Security Council to take immediate action to respond to this unprovoked act," White House spokesman Tony Snow said in a statement.

The spokesman stopped short of confirming the DPRK nuclear test but said that the United States and South Korean intelligence detected a seismic event Sunday at a suspected nuclear test site in DPRK.

"The United States is closely monitoring the situation and reaffirms its commitment to protect and defend our allies in the region," Snow added.