Helicopters germanwings
French emergency services helicopters travel to the site where Germanwings A320 came down, with 150 people on board, in the southern French Alps.AFP/Getty

Children from a grammar school returning from an exchange programme in Spain were among those killed, it has emerged.

The youngsters included 16 children and two teachers from the English-speaking Joseph-Koenig-Gymnasium in Haltern-am-See, near Duesseldorf. They had been on an exchange trip in Catalonia.

"It was a Spanish language exchange programme and they were flying home after having what was probably the most wonderful time of their lives," said Sylvia Loehrmann, the education minister for the state of North Rhine-Westphalia.

"It's so tragic, so sad, so unfathomable," she said in a report by NDTV. Most of the students were about 15 years old.

Haltern am See mayor Bodo Klimpel said: "It's the darkest day in this town's history," who added that some parents still drove to the airport and some to the school, hoping for news. "We're in a state of shock. It's the worst thing ever imaginable."

German leader Angela Merkel has travelled to the disaster scene to offer condolences to the bereaved families.

It is believed about 100 Germans in total were killed in the disaster. Media reports suggested the other passengers were mostly Spanish and Turkish.

Spanish vice president Soraya Saez de Sanataria said 45 people with Spanish surnames were travelling on the Airbus A320. She later said two babies were among the dead.

"Our thoughts and prayers are with the families and friends of the passengers and crew members," said Lufthansa in a statement as the German nation went into mourning for the dead.

A German opera singer Maria Radner, along with her husband and baby were also among the 150 victims of the plane crash, according to a Spanish opera house.

Earlier, it was revealed by an opera house in Duesseldorf that bass baritone Oleg Bryjak was also on board.