A U.S. radar ship capable of tracking North Korean missiles has arrived in Japan, an official said Friday, as the communist nation is forging ahead with preparations for a banned long-range rocket launch.

The USNS Howard O. Lorenzen "made a scheduled port visit" to the port of Sasebo near the Korean Peninsula "as part of the ship's routine presence and operations in the region," Cmdr. Bill Clinton, the spokesman for the U.S. 7th Fleet, told Yonhap News Agency.

The arrival coincides with heightened tensions following North Korea's announcement that it will launch a long-range rocket between Feb. 8-25, a provocation that is sure to add to international outrage over the North's Jan. 6 nuclear test.

The spokesman did not say when the ship arrived or how long it will stay there, but Japanese news reports said that it arrived at the port on Wednesday.

"The ship is part of the U.S. 7th Fleet and is operated by the U.S. Military Sealift Command. Howard Lorenzen supports the U.S.

7th Fleet by providing worldwide, high-quality, dual-band radar data in support of ballistic missile treaty verification," Clinton said.

"The USNS Howard O. Lorenzen is a relatively new ship, having just been christened in 2010. She definitely provides a unique capability for the region," he said.

The USNS Howard O. Lorenzen is the U.S. Navy's newest radar ship equipped with the Cobra King radar system, a new, state-of-the-art mobile radar system consisting of S- and X-band phased radar. (Yonhap)