Former U.S. Senator Ted Stevens, the longest-serving Republican to hold that office, has died in a plane crash in his home state of Alaska.

Stevens was among the victims of the crash late Monday of a small plane (DeHavilland DHC-3T) near a remote Alaskan fishing village.  The National Transportation Safety Board says five of the nine people on the plane are believed to have died.  Officials say the single-engine propeller aircraft went down about 525 kilometers southwest of  Anchorage.

The plane also was carrying Sean O'Keefe, a former administrator of the U.S. space agency, NASA.  Sources briefed about the crash say O'Keefe and his son both survived, but sustained numerous injuries.  O'Keefe, now the North American chief of European aerospace giant and Airbus maker EADS, was on a fishing trip with Stevens, his longtime friend.

Officials say rescue crews did not reach the crash site until dawn Tuesday because of severe weather conditions in the area. The cause of the crash is not clear, but flights in the mountainous region can be perilous even without bad weather.

President Barack Obama issued a statement Tuesday praising Stevens and extending condolences to the late senator's family and the families of those who were killed along with him in the accident.

Stevens' family also released a statement, thanking those working to access the crash area, and offering prayers for all those on board.

In 1978, the former senator was a passenger in a plane crash at Anchorage airport that killed his first wife, Ann.  The 86-year-old Stevens spent 40 years in the U.S. Senate.  He was defeated in 2008 following his conviction for failing to report corporate gifts. The conviction was later overturned because of misconduct by federal prosecutors.

This is the third plane crash in Alaska in less than two weeks.  On July 29, a military plane went down near Elmendorf Air Force Base, killing four people.  Just three days later, a cargo plane crashed in Alaska's Denali National Park, killing all three people on board and sparking a forest fire.

Some information for this report was provided by AP, AFP and Reuters.

A previous version of this story incorrectly cited Anchorage as the capital of Alaska. The state capital is Juneau. VOA regrets the error.