BEIRUT – Syrian soldiers fought rebels Tuesday in a firefight that killed nine people and sent several mortars sailing across the border into the Israeli-occupied Golan Heights.

The Israeli military said nobody was hurt in the shelling and that the spillover was believed to be accidental. But Israel filed a complaint to the United Nations peacekeeping force that patrols the tense region between Israel and Syria.

Over the course of the 18-month-old uprising against Syrian President Bashar Assad, violence has spilled into neighboring Lebanon, Jordan and Turkey. In July, mortar shells fell about one kilometer (half a mile) from the Golan boundary.