Officials are still trying to make contact with some 200 Dutch nationals who have still not been traced since last month’s devastating earthquake in Nepal, the foreign ministry said on Thursday evening.

Some 750 Dutch nationals are thought to have been in the mountainous kingdom when the earthquake struck. Friends and family have reported contact with about 50 of them and a large number have already been flown home.

Some may have managed to leave under their own steam without reporting to the Dutch authorities, news agency ANP says. In addition, contact with people in the most seriously affected is areas is extremely difficult, the news agency says.

At least 12 Dutch nationals are known to have been seriously injured in the quake and are waiting repatriation.