Foreign Minister Yigal Allon today issued a clear warning that Israel would not tolerate the military defeat of its Christian allies in southern Lebanon nor would it permit the destruction of its humanitarian services at open crossing points on the border withLebanon.

In what is considered to be the clearest statement to date defining Israel's responsibility for its allies in southern lebanon, Allon said on television that, as a neighboring country. Isreal could not reamin indifferent to the fate of friendly Lebanese villages close to its borders.

Allon said that as jews who have experienced massacres, Israelis could not permit the slaughter of Christian civilians within israel's reach.

Allon's remarks on television, according to officials here, were a summation of his briefing to the israeli Cabinet today in which he said these views had already been transmitted to all parties involved. The purpose of going public was to make sure that no one misunderstood Israel's position, sources said.

The warning was in response to the heavy increase in fighting along the southern border of Lebanon. The predominantly Christian forces, which have long been backed by Israel, have suffered serious reverses in recent days at the hand of the Palestinians.

Allon reiterated that Israel would not tolerate either a Syrian or a Pan Arab force on its borders or a return of the Palestinians.

Allon went beyond previous statements in declaring Israel's intention not to allow the defeat of its Christian allies - and Moslems and Druze who side with them ' in southern Lebanon and not to allow the destruction of the so-called Good Fence through which Lebanese villagers have been allowed to enter Israel to receive medical attention, to sell their products to work.

Allon's remarks could be seen in context with earlier statements that Israel did not seek a confrontation with Syria and that the best thing for all involved would be to accept the status quo and to deescalate fighting along the border. These remarks were mirrored by Syrian and Palestine Liberation Organization statements that the fighting in southern Lebanon should be halted.

The Israelis have admitted that the recent upsurge in fighting was caused by the Christian forces trying to link up their strongpoints along the border by attacking leftist Moslem-held villages. This offensive caused the Syrians to permit the Palestinians to mount a counter-offensive that has threatened the Christian position all along the line.

Earlier statements seemed to indicate that the Israelis realize the Christians could not realistically expand their position and so the carrot was held out to the Syrians to halt the Palestinian offensive. Today's statement by Allon might be interpreted as the stick to match the carrot saying that although Israel would cooperate in not distrubing the status quo, any attempt to destroy the Christians would risk Israeli intervention.

The foreign minister's remarks might also been as a warning that Israel's also be seen as a warning that Israel's current political difficulties, involving the resignation of Prime Minister Yitzhak Rabin as his party's candidate for relection, should not be interpreted as a weekening of Israel's resolve.

Harold Brown and members of Congress in addition to Carter the announcement said.

In other Middle East developments:

Judicial sources in Tel Aviv said prosecutor Victoria Ostrovsky-Cohen will prepare charges against the wife of Prime Minister Yitzhak Allon in the next two days as a step to bring her to trial for keeping an illegal a count in a Washington bank.

Panama's head of government, Gen. Omar Torrijos, arrived in Tripoli for a five-lay official visit to Libya.

The Foreign Office announced that British Foreign Secretary David Owen will visit Egypt and Syria during the last week in April.