A rare rocket barrage from Lebanon on Thursday deepened Israeli concern that al Qaeda-linked Islamist militants are opening a new front for confrontation with Israel.

The Israeli military said four rockets were fired from southern Lebanon. Two struck Israeli communities without causing casualties, a third was intercepted by the "Iron Dome" missile shield and the fourth fell outside Israeli territory, it said.

A U.S.-based group which monitors Islamist militants said the Brigades of Abdullah Azzam, an organization linked to al Qaeda, claimed credit for the rocket attack.