The 18-year-old youth said to have threatened to shoot a teacher and pupils at a school in Leiden is at the Dutch embassy in Costa Rica, sources have told RTL news.

The youth was staying at a hostel in the country but went voluntarily to the embassy after running out of money, RTL said. He has been in Costa Rica since October last year.

However, a spokesman for the foreign affairs ministry told the broadcaster the youth is no longer at the embassy and that officials will make a statement later.

The public prosecution department said earlier this week it hoped the youth would turn himself in and come back to the Netherlands to face charges. There is no extradition treaty between the two countries.

All secondary schools in Leiden were shut on Monday because of the threat, made via internet forum 4chan.