Russia advised against travel to the Middle East and German airline Lufthansa extended a suspension of its flights to Tehran, as the region was kept on edge by Iran’s threat to retaliate against Israel for an attack in Syria, Reuters reports.

Russia’s foreign ministry told citizens they should refrain from travelling to the Middle East, especially to Israel, Lebanon and the Palestinian territories.

“We strongly recommend that Russian citizens refrain from traveling to the region, especially to Israel, Lebanon and the Palestinian territories, except in cases of extreme necessity,” it said.

“The tense situation in the Middle East region persists,” said the foreign ministry, which first issued such travel advice in October when it urged Russians not to visit Israel and the Palestinian territories.