Approximately 870 Israeli students and teachers are currently in Poland and unable to return to Israel following the joint U.S.–Israeli military strike on Iran, The Times of Israel reports, citing Israel’s Education Ministry.

A study group of 16 people is also stranded in the United States, while nine are in Romania, the ministry said.

According to the ministry, the groups are under the protection of the Shin Bet, as is customary during student trips. There are no indications of any specific risk.

Israel’s Transport Ministry said yesterday that the country’s airspace has been closed at least until Monday, making flights through Ben Gurion Airport and other aviation hubs impossible. Tens of thousands of Israeli travelers worldwide are also unable to return.