Churches have opened their doors in the wake of Tuesday's Germanwings Airbus crash in the French Alps, which killed all 150 people on board.

Sixteen of those who died were teenagers on a Spanish exchange programme from Joseph-Koenig school in Haltern am See, Germany. Two of their teachers were also on the plane.

The local Catholic church in Haltern, St Sixtus, was reportedly open all night for mourners. Hundreds of people visited the church after the news broke yesterday to light candles and write messages of condolence to the families of those who died. At the school just 1.5km away, residents covered the entrance with flowers and red and white candles.

A 16-year-old student, Christopher Schweigmann, told Associated Press that "everyone was in tears in the church".

"It's impossible to believe that they all won't be there anymore in the coming days," he said. He lost two good friends in the crash.

Students in Llinars del Valles, the Spanish town that the German exchange students had visited, also attended a special mass.

Haltern's mayor, Bodo Klimpel, told a news conference that the incident was "the worst thing imaginable."

"It's the darkest day in this town's history... we're in a state of shock," he said. The crash was the largest loss of life for Germany in a single incident for 15 years. In 2000, 97 Germans died in the Air France Concorde crash near Paris.

Deputy Prime Minister of North Rhine-Westphalia, Sylvia Loehrmann, told reporters on Wednesday: "We can only share that pain and maybe some comfort can grow from that sharing. All of Germany is mourning with us and the whole world is sending us messages."

Pope Francis has expressed his solidarity with those in mourning. A telegram sent from the Vatican to Bishop Jean-Philippe Nault of Digne reads: "Having learned of the tragic plane crash in the region of Digne, which caused many casualties, including many children, His Holiness Pope Francis joins in the grief of the families, expressing his closeness to them in sorrow.

"He prays for peace for the deceased, entrusting them to the mercy of God that He might welcome them into His dwelling place of peace and light. He expresses his deep sympathy for all those touched by this tragedy, as well as for the rescue workers working in difficult conditions. The Holy Father asks the Lord to give strength and consolation to all, and, as a comfort, he invokes upon them the abundance of divine Blessings."

Among the victims of Tueday's crash were also two babies. A definitive list of the 150 on board is yet to be produced but it is already known the bulk of victims were German and Spanish, French Prime Minister Manuel Valls said today. Provisional figures suggest that 35 Spanish and 72 Germans died in the incident.

"There's an American, a Moroccan. There are English and Argentines," Valls told reporters on Wednesday.

French Foreign Minister Laurent Fabius added in separate comments to reporters: "The nationalities that are sure are principally Germany and Spain."

"But according to information I've been given there are other confirmed nationalities, which are Argentina, Australia, Belgium, Colombia, Denmark, Great Britain, Israel, Japan, Morocco, Mexico and the Netherlands."

A tweet from CNN claims that the CEO of Germanwings has confirmed two US citizens to have died in the crash.

David Cameron has confirmed that at least three British people were among the victims. Speaking at the Prime Minister's Questions in Parliament today, he said the incident was "heart-breaking".

Addtional reporting by Reuters