An Israeli military source said soldiers at a border outpost opened fire into the air to warn a shepherd spotted crossing the border to cross back into Lebanon. Hizbollah then fired a number of rockets or missiles at the border area, the source said.

The exchanges ratcheted up tensions on the volatile frontier eight days after Israeli forces, backed by aircraft and artillery, and Hizbollah guerrillas were engaged in a clash in the same area.

The May 13 fighting came two days after a rocket fired from south Lebanon hit an Israeli border town.

Hizbollah, backed by Iran and Syria, was instrumental in ending Israel’s 22-year occupation of southern Lebanon in 2000. But the two foes have sporadically clashed in the Shebaa Farms since.

The United Nations says Israel’s withdrawal from Lebanon is complete and the Shebaa Farms is Israeli-occupied Syrian land. Lebanon and Syria say the area is still occupied Lebanese soil.

A U.N. resolution called last year for Syria to withdraw from Lebanon and Hizbollah to disarm. Syrian troops pulled out last month under Lebanese and international pressure.