AMSTERDAM (Reuters) – Dutch authorities identified about 30 war crimes suspects, a third of them Syrians, among the 59,000 people who applied for asylum last year, the immigration minister said on Monday.

Klaas Dijkhoff released the data in a letter amid an increasingly heated debate over immigration, stoked by an increase in arrivals from war zones across the Middle East.

He was responding to questions from members of parliament, many of whom have been calling on the government to start sending back migrants who are suspected of atrocities, or break Dutch laws.

Ten of the suspects were from Syria and the rest from Eritrea, Sudan, Nigeria, Georgia and other countries, he added, without going into further details.

Dijkhoff said the Syrians could not be sent home because international treaties prohibit forced repatriation to a country where there is ongoing conflict.

A backlash against immigration has boosted the Netherlands’ far-right anti-Islam Freedom party, whose leader Geert Wilders is regularly rated the country’s most popular politician.

(Reporting By Anthony Deutsch; Editing by Andrew Heavens)