Six US soldiers were killed when a Blackhawk helicopter was "forced down" in northern Iraq and another died in a separate attack as Turkey announced it was abandoning plans to send troops to help its beleaguered US ally. The bloodshed that has become the daily norm here also claimed the life of another US soldier in Mosul and an Iraqi woman northeast of the capital as Washington readied plans to trim its troop strength in the strife-torn country. The six soldiers, all from the 101st Airborne Division, were killed when the Blackhawk came down outside an American base near Tikrit "The total number of people on board was six. All six have died," said Major Josselyn Aberle, a spokeswoman for the 4th Infantry Division in Tikrit, 180 kilometers (110 miles) north of Baghdad. "They were all from the 101st Airborne Division. They were in a Blackhawk helicopter transporting personnel from Mosul to Tikrit on a routine flight. The cause is still being investigated." Aberle said that officials were looking into reports that loud booms were heard just before the Blackhawk went down. Witnesses were adamant the aircraft had been knocked out of the sky. "I saw one of the helicopters shot from the side and I saw smoke and a ball of fire. I felt happy and started shouting Allahu Akbar (God is greatest)," said Saqr Ghani, who like many here celebrated the setback for the US-led occupation. "I then ran to the car and immediately headed to the river bank where I saw the helicopter cut in two pieces." A farmer, Abu Ahmad, said he had heard a loud blast and saw smoking rising from where the helicopter crashed. US army Specialist Bryan Speckler suggested the attack was similar to the downing of a Blackhawk by a rocket-propelled grenade (RPG) on October 25 just outside Tikrit. "It appears that they were shot in the same manner," said Speckler. "It appears those who shot the helicopter are well-trained individuals because they were good shots from over 400 metres (yards) on moving targets." Earlier Friday, another US soldier was killed and seven were wounded in an RPG attack on their convoy in Mosul, further north, military spokesman Major Hugh Cate said. Near Iraq's northern oil centre of Kirkuk, a fuel pipeline was set ablaze in the latest act of sabotage against the key revenue earner for the country's post-war reconstruction, oil officials said. And in Moqdadiya, 100 kilometers (60 miles) northeast of Baghdad, an Iraqi woman was killed and her husband wounded when a mortar bomb struck their home, the wounded man said Friday. Yunes Ibrahim Hatem, 39, said it was one of four bombs which apparently targeted an adjacent police station, where there are also US troops. In Ankara, Foreign Minister Abdullah Gul announced that Turkey was formally abandoning plans to send troops to Iraq in response to a request from its US ally. "We had already said that we are not that enthusiastic to send soldiers," Gul told reporters. "We had said we would send troops only if we can be of some help. Now we saw that there is not such a situation at the moment and that is why we made this decision." Public opinion in Turkey is said to run more than 80 percent against deploying troops to Iraq. US Secretary of State Colin Powell reportedly told Gul in a telephone call Thursday evening that the presence of Turkish troops could further raise tensions in an increasingly turbulent Iraq. But the announcement marked a setback to US efforts to win troop commitments for an international stabilization force intended to take up some of the burden of patrolling the badlands of western and north-central Iraq. **PHOTO CAPTION*** In this handout picture from the Polish Army, Polish soldiers stand next to the coffin of slain Maj. Hieronim Kupczyk, 44, during a ceremony in Karbala, Friday, Nov 7, 2003. (AP Photo/Polish Army, Vladimir Meciar)