HONG KONG (CNN) -- North Korea surprised the international community Wednesday by launching a long-range rocket just days after suggesting it would be delayed, South Korea's Ministry of Defense said.
"Shortly after the liftoff, Aegis radar system in the Yellow Sea detected the move," a senior military official was quoted by South Korea's semi-official Yonhap press agency as saying. Yonhap added that President Lee Myung-bak has convened an emergency security meeting in Seoul.
The Japanese government confirmed to CNN by phone that it took place at 9.49 a.m. local time and passed over the island of Okinawa, though no action was taken to shoot it down. It said parts of the three-stage rocket came down in the sea off the Korean Peninsula, with another part dropping into the sea near the Philippines.
Chief Cabinet Secretary Osamu Fujimura told reporters at a press conference in Tokyo that Japan had demanded restraint from Pyongyang and that "it is extremely regrettable that North Korea forced the launch despite our protest. It is not acceptable and we strongly protest against it."
Wednesday's news comes as a surprise after North Korea announced Monday that it was extending the launch window into late December, citing technical issues in an engine. On Tuesday, satellite images purportedly showed the rocket being moved from the launch pad, Yonhap said.
The test has been widely condemned by other countries like the United States and South Korea, which say it is a cover for testing ballistic missile technology. The North insists the launch is aimed at putting a scientific satellite into orbit.
When it announced its plans on December 1, the reclusive North Korean regime said it intended to carry out the launch between Monday and December 22. But on Saturday, the state-run Korean Central News Agency (KCNA) said the launch could be delayed.
In a new article Monday, KCNA reported that scientists and technicians had "found technical deficiency in the first-stage control engine module of the rocket," citing a spokesman for the Korean Committee of Space Technology.
Previous launch attempts by the North in 2006 and 2009 also failed to achieve their stated goal of putting a satellite into orbit and provoked international condemnation.
Pyongyang has said the planned rocket launch would be "true to the behests" of Kim Jong Il, the late North Korean leader and father of Kim Jong Un, head of the ruling regime.
Kim Jong Il died on December 17 last year, so the first anniversary of his death falls within the launch window that North Korea has announced.
Experts also speculate that Pyongyang wants this launch to happen before the end of 2012, the year that marks the centenary of the birth of Kim Il Sung, the founder of North Korea and grandfather of Kim Jong Un.