NABATIYEH, Lebanon (AP) _ Shiite Muslim guerrillas raided an Israeli-allied militia post and a U.N.-manned checkpoint in southern Lebanon today, killing one Irish U.N. peacekeeper and wounding another, a U.N. spokesman said.

Lebanese police and sources said eight other people - six fighters and two civilians - were killed and 12 wounded in the pre-dawn assault into Israel's self-proclaimed security zone and an ensuing four-hour retaliatory bombardment.

Timur Goksel, spokesman for the U.N. Interim Force In Lebanon, said the pro-Iranian guerrillas fired a rocket-propelled grenade at a checkpoint manned by Irish peacekeepers, killing a corporal and seriously wounding a private.

The checkpoint in Jmaijmeh is north of the security zone. UNIFIL, as a routine procedure, closes its checkpoints north of the zone after guerrilla raids in order to protect civilians.

Two guerrillas were wounded in the attack, police said.

A total of 187 peacekeepers - including 33 Irish soldiers - have been killed since the 10-nation UNIFIL force was deployed in southern Lebanon in March 1978. The figures include both combat casualties and deaths in accidents such as car crashes.

The area policed by the 6,000-strong UNIFIL overlaps with the security zone, which is controlled by about 1,500 Israeli troops and the allied 3,000- strong South Lebanon Army militia.

Security sources close to UNIFIL said the assailants were from the Iranian- backed Hezbollah. The sources spoke on condition of anonymity.

The guerrillas also attacked a hilltop South Lebanon Army outpost in the village of Rashaf.

According to police, two South Lebanon Army militiamen and four Hezbollah guerrillas were killed in the attack. They said three South Lebanon Army militiamen were wounded.

A 45-year-old Lebanese woman and an 80-year-old Lebanese man were killed and seven other civilians wounded in a four-hour retaliatory bombardment by South Lebanon Army and Israeli gunners on 14 Shiite villages, the reports added.

In Israel, an army spokesman said guerrillas fired a barrage of Soviet- designed Katyusha rockets at the South Lebanon Army post. Israelis sustained no casualties, said the spokesman, who spoke on condition of anonymity.

It was the fifth straight day of hostilities, which have sent a new wave of tension through the region following the failure of the latest round of Arab- Israeli peace talks to reach a breakthrough.

Hezbollah, or Party of God, which has vowed to sabotage the peace process, claimed responsibility for the attack on Rashaf.

Hezbollah had claimed responsibility for nearly all clashes in the area since Friday, when Israeli troops shot and killed a Shiite guerrilla infiltrator in the security zone.

The security zone was carved out by Israel in 1985 to shield its northern flank against cross-border guerrilla forays.

In Dublin, Ireland, the Defense Department identified the dead soldier as Cpl. Peter Ward, 29, of Athlone. The injured soldier is Pvt. Neil Coleman, 22, of Dublin.