SEOUL >> North Korea may have moved the first stage of a rocket to a launch stand, indicating it is on schedule for a controversial mid-April launch, according to a new analysis of satellite images.

The rocket isn’t visible at the Tongchang-ri site, but an analysis provided to The Associated Press by the U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies says evidence suggests the first stage may be in the launch stand’s closed gantry, a support frame, ahead of the launch planned for April 12-16.

That evidence, seen by the institute in satellite photos taken Wednesday, includes an apparent completion of fueling activity, with most of the empty fuel and oxidizer tanks removed from buildings supplying the first stage; a new barricade for vehicles on the road to the pad, indicating higher security; and the removal of objects near the gantry and a clean-up of the launch pad.

“If past launches are any guide, at least the first stage would have to be present at the gantry if the North Koreans are going to keep to the timetable for the scheduled launch,” said Joel Wit, visiting fellow at the institute and editor of its website on North Korea, “38 North.”

The North Korean launch is meant as a showcase of national power and technology during celebrations of one of the country’s most important days — the centennial of the April 15 birth of national founder Kim Il Sung. North Korea says the rocket will carry a satellite into orbit to study crops and natural resources.

Washington and others call the launch a cover to test missile systems that could target parts of the United States. While North Korea has conducted two nuclear tests, analysts don’t believe it has yet mastered the technology needed to shrink a nuclear weapon and mount it onto a missile.

Launch preparation can also be seen in separate GeoEye satellite images from Saturday reviewed by Allison Puccioni, image analyst at IHS Jane’s Defense Weekly. The images show vehicles on the launch pad, nearby fuel and oxidizer containers and a crane above the launch tower that’s been placed “directly over the mobile launch platform, the position necessary to erect the rocket.”

Cloudy skies from Sunday through Tuesday obscured the launch site, but the U.S.-Korea Institute’s analysis says that if Pyongyang is following a timeline similar to 2006 and 2009 launches, workers should have put the rocket’s first stage on the launch stand Sunday or Monday, with the second and third stages coming during the next two days.

Any launch would likely destroy a Feb. 29 accord between North Korea and the United States that would ship U.S. food aid to the impoverished North in exchange for a moratorium on missile and nuclear tests, as well as a suspension of nuclear work at its main Yongbyon nuclear facility. The U.S. says plans to provide food to the North are already on hold.

North Korea has conducted three such launches since 1998. The last launch, in 2009, led to U.N. condemnation and the North walking away from six-nation nuclear disarmament talks; weeks later, Pyongyang carried out its second nuclear test.

In 2010, 50 South Koreans were killed in attacks blamed on North Korea.