A plane carrying former U.S. senator Ted Stevens and ex-NASA chief Sean O'Keefe crashed near a remote fishing village in Alaska, killing the longtime senator and at least four others, authorities said Tuesday.

Former U.S. Republican senator Ted Stevens, seen in this October 2008 photo, was among five people killed in a plane crashed in remote southwest Alaska. (Hyungwon Kang/Reuters)

O'Keefe and his teenage son survived the crash with broken bones and other injuries, former NASA spokesman Glenn Malone said.

The crash was a stunning event in a state where Stevens became the most beloved political figure in Alaska history during his 40 years in the Senate, earning a reputation as a tireless advocate for projects that brought millions of federal dollars to the state. He was 86.

Stevens and O'Keefe are longtime fishing buddies who had been planning a trip near where the float plane crashed while carrying nine passengers.

The plane crashed into a brush- and rock-covered mountainside sometime Monday night, authorities said. Volunteer pilots were dispatched to the area around 7 p.m. local time after the plane was found to be overdue at its destination, and they came upon the wreckage about a half hour later.

The weather soon took a turn for the worse, with heavy fog, clouds and rain blanketing the area and making it impossible for rescuers to arrive until after daybreak Tuesday. O'Keefe, his son, and two others were flown to the hospital.

Alaska National Guard spokesman Maj. Guy Hayes offered no details about the conditions of the survivors or their identities.

National Transportation Safety Board spokesman Ted Lopatkiewicz said the agency is sending a team to the crash site outside Dillingham, located in Bristol Bay more than 500 kilometres southwest of Anchorage. The aircraft is a 1957 DeHavilland DHC-3T registered to Anchorage-based GCI.

The cause of the crash was not immediately known, but the flights at Dillingham are often perilous through the mountains, even in good weather.

Federal Aviation Administration spokesman Mike Fergus said the plane took off Monday afternoon from a GCI corporate site on Lake Nerka, heading to the Agulowak Lodge on Lake Aleknagik.

Fergus said the plane was flying by visual flight rules, and was not required to file a flight plan.

'Devoted his career' to Alaska: Obama

Stevens was appointed to the Senate in 1968 and served longer than any other Republican in history. He was revered as a relentless advocate for Alaska's economic interests.

"A decorated World War II veteran, Sen. Ted Stevens devoted his career to serving the people of Alaska and fighting for our men and women in uniform," U.S. President Barack Obama said in a statement.

"Michelle and I extend our condolences to the entire Stevens family and to the families of those who perished alongside Sen. Stevens in this terrible accident."

Over the years, Stevens directed billions of dollars to Alaska. But one of his projects — infamously known as the Bridge to Nowhere — became a symbol of pork-barrel spending in Congress and a target of taxpayer groups who challenged a $450-million US appropriation for bridge construction in Ketchikan.

Stevens' standing in Alaska was toppled by corruption allegations and a federal trial in 2008. He was convicted of all seven counts — and narrowly lost his Senate seat to Democrat Mark Begich in the election the following week.

But five months after the election, U.S. Attorney General Eric Holder sought to dismiss the indictment against Stevens and not proceed with a new trial because of prosecutorial misconduct by federal prosecutors.

Stevens was one of two survivors in a 1978 plane crash at Anchorage International Airport that killed his wife, Ann, and several others. He remarried several years after the crash — he and his second wife, Catherine, have a daughter, Lily. The airport in Anchorage is now named after Stevens.