Israel launched an airstrike on Beirut for the first time since a U.S.-backed cease-fire took effect in November, amid growing frustrations among some American officials about the Lebanese government’s slow progress in disarming Hezbollah in the country’s south.

Friday's air raid by Israel was the first in the Lebanese capital's southern suburbs and raised fears of a return to war.

Israel threatened a severe response to three rockets it said had been fired from Lebanon Saturday, prompting the Lebanese prime minister to warn the country risked being dragged into a "new war".A fragile ceasefire that took effect on November 27 has been marred by repeated accusations of violations by both sides but the Israeli warning marked the biggest threat so far to the relative calm it had brought to border areas.