JERUSALEM (AP) — Three Syrian tanks entered the demilitarized zone in the Golan Heights on Saturday, prompting Israel to complain to U.N. peacekeepers, a military spokesman said. The foray would be the first such violation in 40 years and hikes concerns that violence from Syria’s civil war could heat up a long-quiet frontier.

Israel’s relatively low-key response of turning to the U.N. suggested it did not see the Syrian armor as an immediate threat.