An Israeli military helicopter crashed and burned during a night excercise near Jericho in the occupied west Bank of the Jordan River yesterday killing 50 paratroopers and four crewmen, the government announced today. There were no survivors.

The cause of the accident is under investigation, but hostile fire has been ruled out even though the crash took place within 5 miles of Jordanian lines. The government embargoed the news until today so the army could notify the families of the dead.

It was Israel's worst military air disaster.

In a small country such as Israel which has emotional attachment to its army and where almost everyone has a relative in the services, the crash has caused national shock and grief.

Tomorrow the funerals will begin, and Israeli flags will fly at half staff. A special session of parliament that was to be held tomorrow has been called off.

By consent of all the political parties, all campaign activity leading up to next week's general election was canceled for today.A national television debate, between the leaders of Israel's two major political parties, Shimon Peres and menachim Begin, scheduled for tomorrow has been postponed.

Festivities and performances involving artists and music in the streets that were to mark the 10th anniversary of the reunification of Jerusalem have also been canceled.

Defense Minister Shimon Peres visited the scene of the crash along with Chief of Staff Mordechai Gur.

The helicopter, a Sikorsky CH-53 of American manufacture, was involved in a night exercise near the Jewish settlement of Naaran, just north of Jericho. It lifted into the air at about 8:40 p.m. without any apparent difficulty, Gen. Gur said at a press briefing. Soon after take off it began to lose altitude and crashed onto the desert floor.

Hostile fire has been ruled out as has overloading.

Two weeks ago, a report by the government comptroller criticized the military for being careless with its equipment. When asked whether negligence in maintenance may have been a factor in the crash, Gen. Gur said it was too early to tell.

Some of the bodies were so badly burned that positive identification of individuals has not yet been made, Gur said, but before an Israeli unit boards an aircraft each man signs his own name to a manifest, and this list has been checked with the army's computers.