Sixteen children from the same school in Germany were on board the passenger plane that crashed in France carrying 150 people.
North Rhine-Westphalia state Education Minister Sylvia Loerhmann said: “We know that the school group boarded the plane,” the dpa news agency quoted her as saying.
The Germanwings plane, which was travelling from Barcelona to Dusseldorf, crashed in the French Alps between Barcelonnette and Digne carrying 144 passengers and six crew.
There are not thought to be any survivors.
The school the children had visited, about 45 minutes from Barcelona, said 16 students from the town of Haltern had been on an exchange trip that ended on Tuesday.
Marti Pujol, mayor of the village of Llinars de Valles, said: “There were 16 children and two teachers who had spent a week here, poor things.
“The children were aged about 15.”
Media reports in Germany said earlier that the schoolchildren and teachers were from Joseph-Koenig Gymnasium high school in the town.
The headmaster of the school has sent students home, and parents have gathered at Dusseldorf airport, Halterner Zeitung reported.
Local police are still awaiting official confirmation, but they have already sent officers to the school to help students and staff.
The school has so far refused to comment.
At a press conference, Germanwings said there were two babies on the flight.
Sobbing and grieving families at both Barcelona and Dusseldorf airports were led away by airport workers and crisis counsellors.
Family members arriving at Dusseldorf were taken from the main terminal to a nearby building, which has been partially covered with sheets for privacy.
In Barcelona, police escorted several crying women to a secure part of the airport. One held a jacket over the head of another woman, who was sobbing.
The aircraft started descending one minute after reaching its cruising height and continued losing altitude for eight minutes.
Germanwings managing director Thomas Winkelmann said: “The aircraft’s contact with French radar, French air traffic controllers ended at 10.53 am at an altitude of about 6,000 feet.
“The plane then crashed.”
A total of 67 Germans are believed to have been on board, as well as 45 Spaniards.
The country’s chancellor, Angela Merkel, will travel to the region on Wednesday.
She described the crash as “a shock which has plunged us into deep mourning in Germany, France and Spain”.
The German leader added: “What concerns me now is the extent of the suffering, which this catastrophe has brought to so many people.
“My thoughts and condolences, and those of the entire government, go out to the people who have lost their lives, including many compatriots.”
Ms Merkel has urged people not to speculate on the cause.