The bus company whose coach has crashed in France says it is still trying to make contact with organisers.
There were two drivers and 48 passengers on board.
The children aged between 13 and 18 years old set off for Italy yesterday afternoon. They were from a school in England.
Express Motors is in the process of doing everything they can to contact their drivers and designated tour leaders. When they have made contact they will be doing everything they can to help.
Once contact is made they will do everything they can do to help accident teams with their investigations and inquiries.
Pictures show multiple emergency vehicles and a helicopter at the scene of a bus crash in France.
It's understood the coach is from north Wales company, Express Motors.
The Foreign Office says it is working with relevant local authorities in France after a coach crash.
“We are providing support to a group of British nationals following a coach crash in France. We are in contact with the relevant local authorities.”
Most of the passengers on board a bus which crashed in France are ''aged 14 to 17" according to reports.
News agency AFP is reporting that the crash took place near Lons-le-Saunier, near the Swiss border.
It's understood the bus, believed to be carrying teenagers from Wales, ended up on its side in a ditch and that two helicopters were sent to the site.
A coach reportedly carrying teenagers has crashed in France injuring 13 passengers.
Three are believed to be seriously injured.
The bus crashed on its side on a motorway near Lons-le-Saunier, near Swiss border as it was travelling to Italy.
There were 48 people on board, most of whom were aged between 14 and 17.
A couple from Ystradgynlais have described a feeling of "mass panic" in Munich after a shopping centre shooting.
Mike and Cynthia Davis flew out to the German city yesterday and were in a Bierkeller on the main square when the attack happened.
We'd just got our drinks. My husband and friends heard what we thought was thunder we didn't hear it. Mike said just get on the floor get on the floor and then we heard shots
We hadn't even had a drink. there was no mistaking that they were shots. We could definitely hear it. There was mass panic. People were screaming, running. We were laying on the floor. People just running over us to get out. Mike laid on top of me. It was packed with a thousand people.
The attack at the shopping centre left nine dead and several injured and was carried out by a lone gunman.
The gunman, who then killed himself, has been identified as an 18-year-old German-Iranian who was living in Munich but he was not known to police. The motive for the attack is still unclear.
Thomson and First Choice which operate out of Cardiff Airport say flights to Dalaman, Antalya and Izmir are operating as normal after more than 160 people were killed in an attempted military coup in Turkey.
In a statement they said:
Given these exceptional circumstances, customers due to depart on 16th July 2016 and who no longer wish to travel, can cancel and receive a full refund, or amend to another holiday currently on sale subject to availability.
All flights departing on Monday 18th July 2016 are operating as normal.
Normal booking conditions apply for all other travel dates to Turkey. We will continue to closely monitor the situation as it develops, together with the relevant authorities."
Cardiff Airport advise passengers expecting to travel to turkey in the next few days to monitor Foreign Commonwealth Office travel advice and check with tour operators and airlines before travelling.
Thomas Cook is advising its customers to "stay in their hotels until further notice".
A spokeswoman for the company said: "We note the reports coming out of Turkey regarding a military coup. There is no indication that guests in the coastal resorts are affected.
"However, as a precautionary measure, we advise our customers in resort to stay in their hotels until further notice.
"There has been no change to Foreign and Commonwealth Office (FCO) advice regarding travel to Turkey and our flight and holiday programme is operating as normal.
"However, given the circumstances, we are offering free amendments and cancellations for all customers due to fly to Turkey on Saturday July 16 and Sunday July 17.
"We are monitoring the situation closely and will update when we have further information.
A vigil has been held on the steps of the Senedd in Cardiff Bay following the tragedy in Nice last night. At least 84 people have been killed after a lorry was driven into crowds celebrating Bastille Day.
Speaking at the vigil, Marie Brousseau-Navarro, the honorary consul of France in Cardiff, said it was comforting to see Wales show solidarity in wake of the terror attacks in Nice.