TOKYO ? Japan on Saturday launched a next-generation spy satellite as part of efforts to beef up its surveillance system against the threat of North Korea's missiles, officials said.

An H-2A rocket carrying the nation's No. 3 Information Gathering Satellite was launched Saturday morning from Tanegashima Space Center on Tanegashima Island, southwestern Japan, the officials said.

"We successfully separated the satellite from the rocket and put it into orbit," said Toshimitsu Ozeki, an official of Mitsubishi Heavy Industries, which built the rocket.

The government-run satellite will replace the first model, with an advanced optical device to distinguish objects on the ground with a resolution of some 60 centimeters (24 inches), the officials and local media said.

The new satellite will undergo a performance trial for about three months before starting fully-fledged operations, Kyodo News reported.

The launch is the nation's latest effort to build an intelligence-gathering system following North Korea's missile launch in 1998 over the Japanese archipelago.

In defiance of international pressure, North Korea launched again what was believed to be a three-stage Taepodong-2 missile in April, with an estimated range of 6,700 kilometers (4,100 miles).

Japan currently operates two optical satellites and a radar satellite, while planning to add another radar satellite by March 2013 to complete the system so that it will be able to monitor designated places on the Earth once a day.

The satellite launched Saturday cost about 48.7 billion yen ($580 million) for research and development and around 9.4 billion yen for manufacturing and the launch, Kyodo said.