Japan launched two intelligence satellites into orbit on Sunday amid growing concerns that North Korea is planning to test more rockets of its own and possibly conduct a nuclear test.

Officials say the launch Sunday of the domestically produced HII-A rocket went smoothly and the satellites - an operational radar satellite and an experimental optical probe - appear to have reached orbit.

Japan began its intelligence satellite program after North Korea fired a long-range missile over Japan's main island in 1998. North Korea conducted a launch last month that it says carried a satellite into orbit but has been condemned by the U.S. and others as a cover for its development of missile technology.

The latest Japanese launch was in the planning stages long before the current increase in tensions with North Korea, but underscores Japan's longstanding wariness of its isolated neighbor's abilities and intentions.

The radar satellite, which can provide intelligence through cloud cover and at night, is intended to augment a network of several probes that Japan already has in orbit. The optical probe will be used to test future technology and improvements that would allow Japan to strengthen its surveillance capabilities.