At least 15 Iraqis, including three resistance fighters and four security service personnel, have been killed and many wounded in two separate instances of fighting in Baghdad and Falluja. Four Iraqi Civil Defence Corps (ICDC) personnel were killed and four wounded in heavy fighting north of Baghdad early on Friday. Three fighters too were killed in the encounter, which broke out at around 4:00 am (0100 GMT) near Tikrit, 180km from the Iraqi capital, which also involved US troops, an occupation military spokeswoman said. The wounded were being treated at a nearby military facility. Twenty-one individuals were arrested, she said, but gave no further details. **Falluja clashes*** Eight Iraqi civilians were killed, including three children, after running battles between US occupation forces and resistance fighters in the town of Falluja. According to hospital sources, a further 25 people were wounded in the Friday clashes. Issam Mohammed, a doctor at the main Falluja hospital, said the wounded also included women and old people. Several explosions echoed through the streets, which were deserted apart from ambulances and US military vehicles. A mosque loudspeaker broadcast the call to Friday prayers, but residents had to stay huddled in their homes. US troops turned back reporters trying to reach the town, where explosions and heavy gunfire could be heard from the outskirts. Falluja, about 60km (37 miles) west of Baghdad, has been known for its fierce hostility to the US-led occupation. The US military had no immediate word on the fighting in the town. **Explosions*** In Baghdad, at least six civilians were wounded, including a young child, in a series of blasts on Friday evening, hospital officials said. Doctors at Baghdad's Yarmouk hospital said three men, a woman, a teenage boy and a child were brought into the emergency room shortly after the explosions. Two were seriously wounded and moved to another hospital. There were reports of blasts in several places. It was not clear what caused them. In one residential district, blood stained the road and there was a hole from the impact of what witnesses said could have been a mortar or rocket. "I was standing with my friends and then we heard a strong blast," Muhammad Sahib, a 16-year-old being treated in Yarmouk, said. "Something fell on us from the sky. I don't know what it was, a missile or something else." **Pipeline fire*** Meanwhile, another crude oil pipeline feeding southern Iraqi export terminals is on fire. A British military spokesman said they understood that a pipeline valve had failed and fire broke out from the spillage. The British army, which controls occupation forces in southern Iraq, said there were no explosives involved in the incident. Iraqi guards on duty at Shuaiba, an area near the city of Basra, said alleged saboteurs ignited oil that leaked from the pipeline on Friday. A pipeline network fed from southern oilfields passes through Shuaiba on the way to Gulf export terminals. British occupation soldiers were on the scene as huge flames and clouds of smoke rose into the air. An explosion damaged another oil pipeline in southern Iraq on Wednesday but the main crude export link to the Basra oil terminal was not affected, officials said, adding that a technical fault was likely behind the explosion. **PHOTO CAPTION*** An American humvee burns after it came under attack during a shootout in the Iraqi town of Fallujah, west of Baghdad, Thursday March 25, 2004. (AP Photo/Khalid Mohammed)