Two Israeli F-15 jet fighters collided and crashed in a training exercise over the country, informed sources said Monday.

There were no details. Nor was there any immediate announcement in Jerusalem, where strict censorship usually delays announcements of military accidents or other incidents considered to be matters of national security.Israel's 48 F-15 fighters were obtained from the United States and are considered one of the most potent weapons in the Israeli arsenal.

Normally, training exercises with the high-flying jets are conducted over the Negev desert in the southern area of the country.

The F-15, nicknamed the Eagle by the U.S. Air Force, is the most advanced, land-based jet fighter in the American inventory. Made by the McDonnell Douglas Corp., the twin-engine jet is designed to fly and fight in all weather conditions and can fly at more than 21/2 times the speed of sound.

Israel is one of few foreign countries that has been allowed to acquire the plane.

In recent years, the F-15's safety record has helped the U.S. Air Force reduce its overall accident rate to some of the lowest marks ever.

The F-15 is normally armed with one internal 20mm cannon and two types of air-to-air "dogfighting" missiles, the Sparrow and Sidewinder. The single-seat fighter has a combat altitude ceiling of 65,000 feet.