North Korea could test-launch a missile this year from its second and more sophisticated launch site, in an apparent move to improve its long-range missile capabilities, a U.S. expert said Tuesday.

  South Korean and U.S. officials have monitored the new Tongchang-ri missile base on the North's west coast for more than two years, and satellite images showed early this year that construction of a launch tower at the base was nearly completed.

  "What I can tell you is that the facility is pretty close to being ready to use. ... A trial launch at the Tongchang-ri site? I think that's possible that they could do it this year," Bruce W. Bennett, a senior defense analyst at RAND Corporation, a U.S. think tank, told Yonhap News Agency in an interview in Seoul.

  Bennett, however, said he has no substantive evidence North Korea was preparing for a missile launch, and part of the aim of the Tongchang-ri base is to put a satellite into orbit.

  "So they have to do a number of tests to prove that they could launch a satellite," Bennett said. "But in the process, a missile that can reach the United States could be tested."

  In January, U.S. Defense Secretary Robert Gates publicly said that North Korea could develop missiles within five years that would directly threaten the U.S.

  North Korea test-launched a long-range Taepodong-2 missile in 2006, but it exploded 40 seconds after launch. Another Taepodong-2 traveled some 3,200 kilometers and landed in the Pacific Ocean in 2009.

  Tensions on the Korean Peninsula remain high after North Korea torpedoed a South Korean warship and shelled a southern border island last year, killing a total of 50 people, including two civilians.

  South Korean and U.S. military officials have warned that North Korea could carry out more provocations this year, but the allies have said they are better prepared to respond to such attacks. (Yonhap News)