Israel has launched a strike on Beirut for the second time in days, further testing the shaky ceasefire with Hezbollah struck four months ago.

Israel delayed a promised troop withdrawal in January and has continued to occupy several hilltops in south Lebanon. It has also carried out near-daily attacks on the country, claiming it was striking Hezbollah fighters and weapons.

A Hezbollah official was among four people killed Tuesday in an Israeli strike on south Beirut, Israel and a Hezbollah source said, the second such raid during a fragile four-month ceasefire.