Updated

North Korea has moved a long-range rocket to its northwestern launch site in preparation for a launch next month, South Korean officials said Sunday, as Pyongyang pushes ahead with plans that Washington says are a cover for testing long-range missile systems.

South Korean Defense Ministry and Joint Chiefs of Staff officials said Sunday that the information comes from the South Korean and U.S. militaries. They provided no further details and spoke on condition of anonymity citing department rules.

North Korea says it will launch a satellite into space on a long-range rocket around the April 15 celebration of the centennial of North Korea founder Kim Il Sung. Pyongyang says the launch is part of a peaceful space program.

The United States has warned that the launch could jeopardize a recent deal that would ship U.S. food aid to the North in exchange for a moratorium on missile and nuclear tests.

Washington says North Korea uses such launches as cover for testing missile systems for nuclear weapons that could target Alaska and beyond.

Pyongyang's launch plans are expected to dominate sideline discussions by U.S. President Barack Obama and other world leaders gathering in Seoul for a nuclear security summit. Obama visited the tense border separating the Koreas on Sunday.

The U.N. Security Council condemned North Korea's last long-range rocket launch, in 2009. Pyongyang, which said it was testing satellite technology for peaceful purposes, abandoned six-nation nuclear disarmament talks and, weeks later, carried out a second nuclear test.