JERUSALEM (AP) _ A car exploded near an Israeli army jeep in southern Lebanon on Friday, killing the auto's two occupants but only slightly injuring the three Israeli soldiers in the jeep, a military source said.

The army was investigating whether the car was rigged with explosives or hit a land mine in the incident, which occurred in Israel's self-declared security zone in southern Lebanon, said the source, speaking on condition of anonymity.

Israeli troops searched the area, about six miles north of the Israeli- Lebane se border near the town of Marjayoun.

The military source said the car, a Renault with Lebanese license plates, exploded about 40 yards from the jeep.

Three Israeli soldiers were injured slightly and treated at a first aid station in the northern Israeli town of Qiryat Shemona, the source said.

Israel radio said the army was investigating whether the car was rigged with explosives as part of a suicide mission or hit a road mine.

In Beirut, an anonymous caller told a Western news agency that the driver of the Renault was on a ''heroic suicide operation'' aimed at an Israeli army convoy.

The caller claimed responsibility on behalf of Islamic Resistance, a group of Shiite Moslem extremists seeking to oust Israeli troops from southern Lebanon.

Israel established the security zone, a six- to 10-mile buffer strip north of the border, when it withdrew the bulk of its troops from Lebanon in 1985, ending a three-year occupation.

The zone, a target of frequent attacks by Shiite Moslem and Palestinian guerrillas, is patrolled by about 1,000 Israeli troops and more than 1,000 members of the Israeli-backed South Lebanon Army militia.