Israeli warplanes today attacked three Palestinian guerrilla bases near the northern Lebanese port city of Tripoli in the first such air raid in almost three months.

A military statement issued here said the early afternoon attack struck at two bases of the Syrian-backed rebel Palestine Liberation Organization faction headed by Abu Musa, about five miles northeast of Tripoli. The bases, one of which served as a headquarters for the Abu Musa faction, included a number of one-story buildings, the statement said.

The third target, less than a mile northeast of Tripoli, included bunkers and dugouts controlled by the Popular Front for the Liberation of Palestine-General Command, headed by Ahmed Jabril, the Israeli statement said. The guerrilla bases are all situated in Palestinian refugee camps.

At least 20 people were killed and 55 wounded, security and medical sources in Lebanon said, according to Reuter. Rescuers worked late into the night to control fires caused by the raid.

[After the attack on the base of the Abu Musa faction, Reuter reported, bulldozers rushed to rescue officials of the group's command who were buried under rubble while meeting in the basement of a building there. The faction said seven of its fighters had been killed and 20 wounded.]

The last previous Israeli air raid in Lebanon was on April 17 against a base of another PLO group, the Democratic Front for the Liberation of Palestine.

Israeli officials gave no reason for today's air attack except the continuation of an Israeli policy to strike at Palestinian bases in Lebanon thought to pose a threat to Israel.

"They were, are and will always be targets for air raids," a senior Defense Ministry official said. "We've made it clear that even 50 miles north of the border will not be safe from attacks to disturb their preparations."

Israeli radio tonight said military sources denied any connection between the raids and yesterday's two suicide car bomb attacks at checkpoints in Israel's "security zone" in southern Lebanon. Two Israeli soldiers were wounded and 13 Lebanese civilians and two members of the pro-Israeli South Lebanon Army were killed, in addition to the bombers, identified as Ibtissam Harb, a Druze woman, and Syrian-born Khaled Azrak.

Israel, however, has frequently responded to such attacks with air raids on suspected guerrilla bases in Lebanon, always calling it a continuation of longstanding policy.

The car bomb assaults were among the worst in recent weeks in the security zone. But the Defense Ministry official said no link had been made between these incidents and the decision on when to free the more than 400 Arab prisoners who remain in an Israeli jail and whose release was demanded by the hijackers of a Trans World Airlines aircraft last month.

At the time of the hijacking Israel held about 760 Arab prisoners, most of them Shiite Moslems. It freed 31 during the hijacking and 300 a week ago. Israel has said the timetable for releasing the rest depends on security conditions in southern Lebanon. It denied that the release is linked to the freeing June 30 of American hostages hijacked from the TWA aircraft.

The prisoners "will all be released," the Israeli official said, adding that he was unaware of any definite timetable.

Security sources in southern Lebanon said today that local residents expected the release of more than 100 of the remaining prisoners in about a week.