Hundreds of schools in Hungary received bomb threats on Thursday, officials said, forcing them to briefly evacuate students.
A total of 268 educational institutions nationwide -- most of them schools in the capital Budapest -- got the bomb threats via email, interior ministry official Bence Retvari told reporters.
Authorities so far have found "no direct risk of a bomb attack," he said.
Police are in touch with their counterparts in the Czech Republic, Slovakia and Bulgaria, where schools received similar "Islamist" threats in the past, he added.
Prime Minister Viktor Orban's chief of staff, Gergely Gulyas, said it was too early to say anything about the motive, citing ongoing investigations.
Police have also contacted the EU's police agency Europol in their probe on "endangering public safety".
Police inspected the schools that received threats, after which evacuated students and staff could return, with tens of thousands of students affected.
In May last year, Slovak schools and institutions received more than 1,000 bomb threats.
Hundreds of Czech and Slovak schools were also targeted by bomb threats in early September 2024, with Czech authorities saying they were probing "Russian influence" as one of the possibilities behind them.