JERUSALEM — Israel's military has grounded a fleet of high altitude surveillance drones after one was downed over the Mediterranean Sea.

The military says it intentionally crashed the unmanned aircraft late Saturday because of a malfunction.

The military would not say how many aircraft were grounded. The planes will stay down during an investigation.

An Israeli defense official said the drone was the Israeli-made Heron 1, which flies at high altitudes and can stay in the air for about 45 hours. The official spoke on condition of anonymity because he was not authorized to brief reporters.

Last year, a larger Heron TP drone crashed on a routine flight.

Israel is a world leader in drone technology. Palestinians say Israel uses drones to fire missiles, but Israel does not confirm that.