North Korea on Friday launched a long-range rocket, South Korea's defence ministry and US officials said, with Japan saying that the launch had appeared to have failed.
"North Korea launched a long-range rocket at 07:39 am (2239 GMT Thursday)," a South Korean defence ministry spokesman told AFP.
"US and South Korean intelligence authorities are seeking to determine whether it was a successful launch," he said.
Yonhap news agency also quoted a government source as saying that South Korea was tracking the rocket's trajectory.
Japanese authorities said that the North Korean 'flying object' had fallen into the ocean.
Immediately after the launch, South Korea issued an order urging residents near the inter-Korean border to seek shelter to protect themselves from any debris that might fall from the rocket, Yonhap said.
North Korea has previously said the rocket will place a satellite in orbit for peaceful research purposes, but Western critics see the launch as a thinly veiled ballistic missile test, banned by United Nations resolutions.
The UN Security Council will meet in emergency session on Friday to discuss the situation in North Korea after the launch, a UN diplomat said Thursday.
The diplomat told AFP the 15-member Council would meet "to decide its next step" following the launch, which the United States and several other nations have claimed is in fact a disguised missile test.
Russia's envoy to the United Nations, Vitaly Churkin, earlier said that all Council members agreed that a launch would be a "violation" of US sanctions resolutions imposed in 2009 after Pyongyang's last nuclear test.
US Secretary of State Hillary Clinton on Thursday warned North Korea that if it were to go ahead with the launch, "we will all be back in the Security Council to take further action."
Clinton said the rocket would violate UN Security Council resolutions banning the communist state from ballistic missile activity.
"There is no doubt that this (launch) would use ballistic missile technology," she said.