residential envoy Philip C. Habib met with Lebanese Prime Minister Shafik Wazzan here today in the second day of talks aimed at preventing renewed fighting in southern Lebanon between Israel and the Palestine Liberation Organization.

Across town, near a Syrian Army checkpoint in the Moslem sector, at least eight persons were killed and 20 injured in the explosion of a car bomb.

A man saying he represented the Front for the Liberation of Lebanon from Foreigners claimed responsibility for the attack in a call to Western news agencies.

Although the attack was apparently aimed at the Syrian peace-keeping forces, all of the casualties appeared to be passers-by. Seven persons were killed and 65 injured in three other bombings earlier this week.

Habib declined to comment on the contents of his conversations here, but Prime Minister Wazzan said that Habib's mission was one of "consolidating the cease-fire between Israeli and PLO forces in southern Lebanon and preventing any deterioration such as the . . . threats we've been hearing." His statement was an apparent allusion to a comment Friday by Israel's new ambassador to Washington, Moshe Arens, that an flow of sophisticated Soviet-made arms to the PLO could force the Jewish state to take "some action that would bring about casualties."

Meanwhile, Egyptian officials said in Cairo that the ambassador to the United States, Ashraf Ghorbal, would cut short a planned 10-day visit to Egypt and return immediately to Washington with "urgent" messages for President Reagan and Secretary of State Alexander M. Haig Jr.

[Ghorbal, who arrived in Cairo Friday, met today with President Hosni Mubarak and Foreign Minister Kamal Hassan Ali, who gave him the messages.]