FALLUJAH, Iraq, April 6 (IslamOnline.net & News Agencies) - Meeting fierce resistance from Iraqi fighters, U.S. occupation forces bombarded late Tuesday, April 6, the western city of Fallujah with tanks and warplanes, killing scores of Iraqi citizens.

At least ten Iraqis died when American forces shelled the Golan neighborhood, reported the Doha-based Aljazeera television.

Hospital doctors said another 15 civilians had been killed and dozens injured in the American offensive over the past 48 hours.

The U.S. army reported six Iraqis killed in fighting Monday, though residents said five of them were killed when helicopters hit a residential area.

The occupation troops took control of the industrial area on the town's southeastern outskirts after a fierce six-hour battle with Iraqi fighters.

Iraqi fighters braved the armed-to-the-teeth occupation units with rocket-propelled grenades (RPGs) and mortars, forcing U.S. forces to withdraw from one of their bastions around the city.

Marines pulled back to the outskirts at nightfall to meet heavy exchange of fire on the northeast edge of the city.

Another grinding battle began when a U.S. foot patrol entered a few blocks into the city came under a barrage of fire from a house, leaving at least two Marines wounded.

The trapped patrol called in help and a tank and a Humvee moved in to extract them.

"There is no third option: Either we win martyrdom or force the occupiers to retreat, " one resident told Aljazeera.

Periodic machine-gun fire could be heard in the central and eastern sectors of the city as tanks, amphibious assault vehicles and Humvee jeeps started rolling into the western city backed by A.C.130 gunships and Cobra helicopters.

The operation, dubbed "Vigilant Resolve" involves part of two marine battalions, or more than 2,000 troops.

Some of the worst fighting occurred early Monday when marines set up a checkpoint at the northeastern edge of the city.

They were hit by mortar and small fire simultaneously.

U.S. Marines patrol the outskirts of Fallujah (AFP)

Fallujah residents have appealed Tuesday to United Nations Secretary General Kofi Annan and the international community to intervene and end the crippling U.S. blockade.

Hospital doctors said at least 15 civilians had been killed and dozens injured in the American offensive on Monday and Tuesday.

The only hospital in the city was shelled Monday, April 5, by U.S. helicopters.

Doctors said the situation is extremely serious as some of the injured have bled to death, the Doha-based newscaster added.

The U.S. army reported six Iraqis killed in fighting Monday, though residents said five of them were killed when helicopters hit a residential area.

The occupation troops took control of the industrial area on the town's southeastern outskirts after a fierce six-hour battle with Iraqi fighters.

The town, 50 kilometres (30 miles) west of Baghdad, had been sealed off  at dawn Monday and troops were only letting cars with Fallujah license plates enter or leave the town.

Schools and shops remained closed throughout the day and the streets were deserted, as residents remained indoors.

Marines slapped an 11-hour curfew from 7:00 pm to 6:00 am (1500 GMT to 0300 GMT) on the town.

U.S. forces, meanwhile, have indefinitely closed the highways linking Baghdad to Amman and Damascus that run through or near Fallujah.

U.S. commanders said the bloody incursion came in response to  the killing and mutilation of four U.S. security guards on Wednesday, March 31.

The Fallujah offensive coincides with deadly clashes  between Shiites and U.S.-led occupation troops across the country, which killed at least 87 people and injured some 400 others.

The deaths raised to at least 616 the number of U.S. soldiers killed in resistance operations in Iraq since last year's U.S.-led invasion, according to an AFP tally.