Israel's air force bombed a militant target in Lebanon on Friday in retaliation for a cross-border rocket salvo on Thursday, a spokesman said.
An Israeli military source said the "terror site" bombed was near Na'ameh, between Beirut and Sidon, but did not immediately provide further details.
Four rockets fired on Thursday caused damage but no casualties in northern Israel. They were claimed by an al Qaeda-linked Sunni Muslim group rather than Hezbollah, the Iran-backed Shiite militia that holds sway in south Lebanon.
"Israel will not tolerate terrorist aggression originating from Lebanese territory," military spokesman Lieutenant Colonel Peter Lerner said in a statement announcing Friday's air strike.
Israel and Lebanon are technically at war. Israel briefly invaded Lebanon during an inconclusive 2006 conflict with Hezbollah. The Israelis now are reluctant to open a new Lebanese front, however, given spiraling regional instability.