In the first air battles in the Middle East in five years, Israeli warplanes today shot down five Mig21 fighters of the Syrian Air Force in dogfights over the coast of southern Lebanon, Israeli officials reported.

Israel said it used U.S.-made F15 fighter-bombers as well as Israeli-made Kfir warplanes in the battles near the Lebanese cities of Tyre and Sidon, about 30 miles north of the israeli border. It marked the first aerial combat use anywhere of the sophisticated F15s, sold to Israel in 1976 on the condition that they be used only for self-defense.

It was not immediately clear what effect the renewed hostility between Israel and Syria, a chief opponent of Israel in the 1967 and 1973 wars, might have on peace efforts in the Middle East, especially on the sensitive talks under way between Egypt and Israel.

The Israeli Defense Ministry said it contacted the Egyptian military command and gave it a "full account" of the aerial combat and an air strike against Palestinian targets in Lebanon that led to the dogfights.

The Egyptian government, however, issued a statement condemning the strike on the Palestinians, saying it posed a grave danger to the peace efforts.

Syria claimed that two Israeli aircraft were downed, but Israel said all its planes returned to base following the dogfights and raids.

Israeli military officials said that in addition to the five Syrian planes shot down, two or three others were believed hit by the Israeli aircraft.

[The first reporters to reach the scene found wreckage of two planes, both marked with Syrian air force insignia, the Associated Press reported from Beirut. At least one of the pilots survived, AP said.]

[It also said a rancher in the area reported seeing two Israeli planes downed, one on his property.]

Although Syrian planes have approached Israeli aircraft flying missions into southern Lebanon on several occasions, they have never attempted to engage them in combat.

It was not clear tonight if Syria decided to intercept the Israeli warplanes out of growing frustration with repeated Israeli air strikes into southern Lebanon or whether the incident reflected in some way the instability in Syria arising out of challenges to the government of President Hafez Assad.

Today's Israeli air strike in Lebanon was the third in a week and the tenth in the past two months. The Syrians are known to have beefed up their aircraft detection systems and their antiaircraft emplacements, including Soviet-made SAM missiles.

Syria has about 30,000 troops stationed in Lebanon, placed there as the backbone of the Arab force created in 1976 in an attempt to end the Lebanese civil war.

There were conflicting accounts of today's dogfights issued in Tel Aviv, Beirut and Damascus, with Syria claiming that two "hostile" airplanes were shot down and that four of its own aircraft were hit. The right-wing Phalangist radio in Beirut said an Israeli pilot and crewmember were captured when they bailed out of their damaged aircraft over southern Lebanon.

Israeli military sources called the reports "absolute nonsense" and said that all aircraft returned to bases here.

Israeli Air Force Commander David Ivri said at a news conference that two separate battles unfolded in the skies, one between the coastal city of Sidon and Beirut as Israeli aircraft approached Palestinian targets south of Sidon, and another over Damour, just north of Tyre.

Ivri said each battle lasted no longer than two or three minutes and was fought completely within Lebanese airspace. Israeli officials would not say whether the Syrian planes were downed by cannon fire or air-to-air missiles normally carried by F15s.

Israeli Army Chief-of-Staff Rafael Eitan said the Air Force routinely sends covering aircraft to protect warplanes on sorties against Palestinian bases and that it was these that engaged the Syrian fighters.

Military officials said F4 Phantoms also participated in the air strike, but they would not say how many planes were involved.

Officials said that as the air battles raged, the Syrians tried to reinforce their formation with an additional eight to 10 warplanes, but that the engagement was over before they reached the scene.

Officials said the attacks on the guerrilla bases continued throughout and after the dogfights and that the entire operation lasted about an hour.

Between October 1973, and the end of that war with the signing of the Israeli-Syrian disengagement agreement of May 31, 1974, Israeli and Syrian warplanes engaged in air battles over the Golan Heights.

On April 7, 1967, two months before the outbreak of the Six-Day War, a major aerial battle between Syrian and Israeli planes occurred, in which seven Soviet-made Migs were shot down. During the battle, Israeli Mirage fighters circled Damascus. That infuriated Egyptian President Gamal Abdel Nasser and escalated tensions before Israel's preemptive attack on Egypt.

The Syrian response to today's Israeli air strike came as a surprise to some observers because Israel's choice of targets in recent days had indicated that its Air Force was not taking much account of the presence of Syrian aircraft in the Lebanese skies.

On Sunday, Eight Israeli warplances attacked a string of villages along south Lebanon's Mediterranean highway about eight miles south of Sidon and then struck deep inland in the area of Sohmour, close to Syrian troop positions near the strategic Litani River dam at Lake Qaroun.

By expanding its circle of targets eastward toward the Syrian border, Israel appeared either to be unconcerned about the possibility of being intercepted, or convinced that the need to strike terrorist bases outweighed the risk.

For several months, it has been clear that Israel's objective in its frequent air strikes is to harass the Palestinians into maintaining a constant and debilitating alert and to interrupt their ability to train and equip terrorists.

While attacks in Lebanon once were regarded as retaliatory measures, Defense Minister Ezer Weizman announced following a terrorist raid on Nahariya on April 22 that terrorist bases would be hit "at any time and at any place that Israel deems desirable."

Eitan said today that the air battle would not affect Israel's policy of striking at terrorist bases in Lebanon, enen though both Egypt and the United States voiced concern over the events in Lebanon.