sraeli warplanes today bombed Palestinian neighborhoods and camps on the southern outskirts of West Beirut for the second straight day, following Palestinian claims to have mounted two successful guerrilla raids behind Israeli lines last night.

For about an hour at midday, the planes bombed essentially the same targets they hit yesterday in the first Israeli air raid on the Lebanese capital since June 25. The Palestinian news agency Wafa claimed that 56 persons, nearly all of them civilians, were killed or wounded in today's raids. It said civilian casualties from yesterday's bombardment of West Beirut and the eastern Bekaa Valley came to 182. There was no independent confirmation of the Palestinian report.

The new raids evidently were intended as a warning to speed up negotiations toward a political settlement of the crisis and as a reprisal for mounting Israeli casualties in what is threatening to become a war of attrition with Palestinian guerrillas.

Israeli Foreign Minister Yitzhak Shamir told Israeli Army radio that the purpose of the air attacks was to end what he called Syrian and Palestinian guerrilla violations of the latest cease-fire, The Associated Press reported. Israeli jets hit Palestinian and Syrian positions on Thursday.

"If they cease fire, there will be no fire," Shamir said. Five Israeli soldiers were slain in an ambush Wednesday in eastern Lebanon's Bekaa Valley area, where most of the 30,000 Syrian troops in Lebanon have regrouped following bloody clashes with the Israelis, who invaded June 6.

Reuter quoted one Israeli official as saying: "We hope our message got through to the Syrians and terrorists that the cease-fire is not a one-way street."

"We cannot accept terrorist actions originating from Syrian-held territory since we know the Syrians can stop the terrorists any time they wish," the official said.

The air strikes coincided with talks today among Lebanese leaders to remove obstacles to a political solution that would send 5,000 to 6,000 Palestinian guerrillas out of Lebanon and lift the nearly six-week-old Israeli siege of West Beirut.

After meeting Prime Minister Shafiq Wazzan, Lebanese Moslem leader Saeb Salam said he had proposed a new idea to resolve disagreements over a Palestine Liberation Organization proposal to send its trapped fighters to northern and eastern Lebanon until a country of refuge could be found for them. Salam, a former prime minister, said that in addition to Israeli rejection of the idea, Lebanese politicians and residents of the areas have expressed opposition to any such measure.

Salam said he proposed today a strict timetable limiting the period the fighters can spend in either place. He said he still held out hope that Syria would reverse its refusal to accept the guerrillas and agree to take them in.

This subject is believed to have come up today in talks between U.S. special Middle East envoy Philip C. Habib and Syrian leaders in Damascus. According to reports from the Syrian capital, Habib conferred with President Hafez Assad and Foreign Minister Abdul Halim Khaddam on the first leg of a tour that will also take him to Saudi Arabia, Israel and Egypt.

U.S. Embassy officials, who are maintaining a strict silence on the negotiations between Habib and Lebanese leaders in the Israeli-occupied suburb of Baabda, are understood to expect Habib to return to Beirut after his tour.

According to the state-run Radio Lebanon, the Israeli planes today bombed Palestinian camps and working-class Lebanese neighborhoods around Beirut Airport south of the capital. The Fakhani district on the outskirts of West Beirut, where some PLO offices are located, was also reported hit along with an area by the coastal road south of the city were remnants of a Syrian peace-keeping force still are stationed.

Palestinian guerrillas and their Lebanese Moslem allies in the besieged western half of the capital fired antiaircraft guns at the planes, to no avail.

The PLO news agency, meanwhile, reported that a commando unit of the Palestinian-Lebanese "Joint Forces" attacked an Israeli "command post" last night in the occupied city of Sidon 27 miles south of Beirut.

Wafa claimed that "at least one senior Israeli officer was killed and others wounded" in a 30-minute attack with machine guns, hand grenades and bazookas. Following the attack, it said, a curfew was imposed, the city was sealed off and the authorities began hunting for the guerrillas, searching homes and arresting a number of persons.

At least some of the searches and arrests were carried out by Lebanese Christian militiamen of the Phalange Party, according to reports from the port city. The Phalangists have taken advantage of the invasion by their de facto Israeli allies to expand their control to new areas, including Sidon.

Later, Wafa reported that another guerrilla unity "operation behind enemy lines" had attacked an Israeli position at Baalshmay near Bhamdoun on the Beirut-to-Damascus road last night. The agency claimed that "several Israeli armored vehicles were destroyed and a number of Israeli soldiers killed or wounded in the attack."

Israel has charged that guerrillas have been infiltrating from Syrian-controlled areas in eastern Lebanon to carry out raids and ambushes.