Undated (AP) _ By ANWAR FARUQI Associated Press Writer

ABU ZAKR, Iraq (AP) - Shiite Muslim guerrillas fighting in southern Iraq's Howeizah marshes fear two things above all else - Saddam Hussein's gunships, and the road his engineers are building to move his tanks into the heart of the rebel stronghold.

Every day, flights of gunships - Soviet-made Mi-24 Hinds and French-built SA-342 Alouettes - prowl the skies above the swamps, rocketing everything in sight. The rebels have no surface-to-air missiles to counter them.

The ruined town of Saleyn, where thousands of Shiite refugees are holed up, was hit by three gunships Thursday. Jaffar Ghanem, a boy of 15, said: ''We're afraid of the helicopters because they're usually very accurate. The artillery nearly always miss us.''

The gunships were once an occasional menace. Now they're in the air every day as the fighting intensifies.

To the north, where there's a big rebel concentration, Saddam's forces are slowly pushing a dirt road into the marshes, where boats are the main form of transportation. So far, the rebels say it's not a problem.

But they know it will be, because it will allow the Iraqis to thrust their armor and big guns into the swamps, exposing the rebels' bases.

The road is heavily guarded, which makes sabotage operations dangerous and difficult. But Hassan Khalaf Hussein, a rebel chieftain, said there have been repeated attacks to slow construction down.

''So long as we only have to fight other men we can hold out,'' he said. ''But tanks and artillery are something else altogether.''

The rebels, armed only with automatic weapons, some rocket-propelled grenade launchers and a few B-3 recoilless rifles, have nothing to combat armor.

No one knows for sure how many rebels there are in the marshes, which cover about 6,000 square miles of southeastern Iraq. But rebel leaders estimate there are around 10,000.

There are also some 200,000 Shiite refugees and army deserters, living hand-to-mouth on fish they catch in the muddy waterways, what they can grow themselves and on sporadic supplies brought in from Iran.

They've been holed up there since March last year, when Saddam's Republican Guards crushed a Shiite rebellion right after Iraq's Gulf War defeat.

Outgunned, outnumbered, riddled by disease, all but forgotten by the outside world, the rebels are fighting for survival against the most sustained offensive the army has mounted in the last year.

''Saddam wants to exterminate us,'' said Hussein, a marsh dweller who only took up the gun when the army rampaged through the south, wreaking a terrible vengeance on the Shiites.

''We have no choice but to fight. If we returned to our homes we'd be dead men.''

The lanky, bearded Hussein commands several dozen rebels near Abu Bakr village in the heart of the marshes a few miles from the Iranian border.

His band has been in constant combat for months with hit-and-run raids against army patrols.

''For a while things weren't too bad,'' the 35-year-old former fisherman said. ''We were up against the regular infantry units and they weren't much of a problem. But in the last few weeks things have changed dramatically.''

The army launched its new push April 15 and this time, the rebels say, the Republican Guard is the spearhead, thrusting into the labyrinthine swamps from the north, south and west.

If the rebel claims are accurate - and during this correspondent's three days in the marshes, the thunder of artillery never stopped - Baghdad has at least 36,000 men and probably more in action.

There appears to be little overall control or coordination among the guerrilla bands.

Nominally, they're under the command of the Tehran-based Supreme Assembly of the Islamic Revolution in Iraq, the main Shiite opposition movement in exile.

But it's clear that the rebel army is little more than a loose coalition of small groups operating as they please, often with no contact with other groups.

Still, their morale appears high, despite the army's superior numbers and the privations of living in the marshes - the disease, the lack of medicine and supplies.

The Shiite dissidents have not fared as well as the autonomy-seeking Kurds in northern Iraq, who were given a protective umbrella by the U.S.-led Gulf War allies when their uprising was also crushed last year.

Under the Gulf War cease-fire, Iraq is not allowed to fly fixed-wing aircraft in Kurdish areas. There are no such restrictions in the south.