JERUSALEM (AP) — Dozens of armed men gathered on the Syrian side of the cease-fire line in the Israel-controlled Golan Heights Wednesday, prompting authorities to close a tourist site as a precaution, the Israeli military said.

An Israeli spokesman said it was unclear what the armed Syrians were doing. He said there was no violence or attempts to cross the border. He spoke on condition of anonymity under military rules.

Israeli forces there were on alert.

The armed men were not wearing uniforms. It was not clear if they were soldiers from the Syrian army or rebel forces battling President Bashar Assad's regime.

Israelis are concerned that fighting from Syria's civil war could spill across the border. Last month, several mortar shells exploded in Israeli-controlled territory. Nobody was hurt. Israel said the shells were misfired.

Israeli officials have also expressed concern that the frontier region could turn into a lawless area like Egypt's Sinai desert, where Islamic militants have gained strength since the ouster last year of Egyptian President Hosni Mubarak.

Israel and Syria have been bitter enemies for decades, but there is concern in Israel that if the Assad regime is toppled, the country could fall into the hands of Islamic extremists or descend into sectarian warfare, destabilizing the region.

An Israeli tour group visiting Mount Hermon, the Golan site closest to the border spot, left without incident, and the site was temporarily closed Wednesday as a precaution. "It happened far away from the site, but to be on the safe side, the tourists were told to go down from the mountain to the lower part of the resort," said Shaul Ohana, who manages the site.

Last year in a demonstration, thousands of people stormed the border fence from Syria, and hundreds burst through. At least 15 infiltrators were killed that day in clashes on the Syrian and Lebanese borders.

Israeli officials accused Damascus of promoting the clash to try to divert attention from the violence within Syria.

Since then Israel has beefed up security in the area.

Israel captured the Golan Heights from Syria in the 1967 Mideast war. It later annexed the strategic territory overlooking northern Israel in a move that is not recognized internationally.