Six people who died in a plane crash in Alabama on Sunday were three married couples, media in the US state say.

Authorities say the plane crashed just short of the runway at Tuscaloosa airport, shortly after sending a distress signal.

Reports say the couples had been returning to Oxford, Mississippi, after a dental conference in Florida.

The Eagle newspaper in Oxford said 11 children were orphaned by the crash. None of the children were on board.

The plane sent a distress call at about 11:10 (16:10 GMT) on Sunday, Bobby Herndon, the mayor of the community of Northport near Tuscaloosa, said.

It came down in trees close to the airport and rescue crews were on the scene within three minutes, but no-one survived, he said.

The Alabama broadcaster WBRC quoted a relative as saying that Jason and Lea Farese, two dentists from Oxford, were among those killed.

The Oxford Eagle said they had three children, aged 10, seven and five. The youngest started kindergarten this week, the newspaper said.

One other couple on board had five children, it added.