BEIRUT (AP) - Syrian rebels have been attacking a government airbase in the north of the country.

Activists say the assault is aimed at disrupting strikes by warplanes and helicopters that have pounded rebel-held towns and given the regime of President Bashar Assad a major edge in the civil war.

Meanwhile, Israel's military says three Syrian tanks have entered the demilitarized zone in the Golan Heights. A military spokeswoman says Israel has complained to the U.N. peacekeeping force in the area.

The relatively low-key response suggests Israel does not regard the armor as an immediate threat. There are concerns in Israel that violence from Syria's civil war could spill over a long-quiet frontier.

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