MANILA, July 21 (Reuters) - A U.S. B-52 bomber that was due to fly in a Liberation Day parade in the U.S. territory of Guam on Monday crashed into the Pacific Ocean soon after take-off, news reports and officials said.

At least six crew members were missing, according to the website of Kuam News, a local station.

The U.S. airforce said in a statement it had no information on the status of the crew. It did not say how many people were on board the bomber or give a reason for the crash, which happened at 9:45 a.m. (2345 GMT), 15 minutes before the parade was about to start.

An air force official was quoted on the Pacific Daily News website saying the plane was meant to take part in the parade.

July 21 is the day Guam commemorates its 1944 liberation from Japanese occupation in World War Two.

The island, under U.S. control since 1898, is the only significantly populated U.S. territory to have ever been occupied by a foreign power.

In February, a B-2 stealth bomber, which costs around $1.2 billion, crashed at Andersen Air Force Base on Guam. The two pilots on board ejected safely. (Reporting by Carmel Crimmins; Editing by Alex Richardson) (carmel.crimmins@thomsonreuters.com; Reuters Messaging: carmel.crimmins.reuters.com@reuters.net; + 63 2 841 8934))