Two Israeli soldiers have been killed in an attack by the militant group Hezbollah on its forces near the border with Lebanon.
The news was confirmed by the Israeli Defence Force (IDF).
Meanwhile the UN has urged maximum restraint after a Spanish peacekeeper was killed in southern Lebanon amid border clashes between Hezbollah and the Israeli army.
Spain’s Prime Minister Mariano Rajoy confirmed that one of his country’s soldiers had died, sending his condolences to the family.
The threat of a wider conflict between Israel and Hezbollah has increased after an anti-tank missile fired by the Lebanese militant group hit an Israeli army vehicle, killing the two soldiers and wounding another seven, according to the IDF.
Mortar bombs were also fired at Israeli-occupied areas close to the Lebanese border. Hezbollah claimed responsibility.
Israel responded with artillery fire, shelling several Lebanese border villages.
Earlier Israel struck at Syrian army positions after rockets were fired from Syria into the Israeli-occupied Golan Heights.
Israeli Prime minister Benjamin Netanyahu vowed that Israel would respond with force if attacked.
Speaking from Sderot in southern Israel he said: “I suggest that those who try to challenge us on our northern border see what happened here,” referring to last year’s war with Gaza.
Israel’s northern border has been largely quiet since 2006 when Israel and Hezbollah fought a month-long war.
Israel has been warning about Hezbollah activity along its frontier, including the possibility that the militants might dig tunnels into Israeli territory. In recent days it has been moving troops and military equipment into the area.