A joint US-Iraqi force targeted an al-Qaida cell involved in funneling arms and weapons into Iraq from Syria, arresting three people near the troubled northern city of Mosul, the US military said Saturday. The statement said the cell is led by the Syria-based Abu Khalaf, whose assets were frozen by the US Treasury department on Thursday for his involvement in the flow of money, weapons and militants through Syria into Iraq. The operation took place in the village of Tal al-Hawa, 50 miles (80 kilometers) northwest of Mosul. "The combined force was led to a residence where they captured three of Abu Khalaf's associates," according to the statement. It added that one of the men was wanted by the Iraqis in connection with car bombings. Another suspected member of al-Qaida in Iraq was arrested in Mosul itself. The operations took place on Friday and Saturday. Mosul, described as the last urban stronghold in Iraq of al-Qaida, has been the scene of a flurry of operations ahead of a June deadline for US forces to pull out of the country's cities. Unlike the rest of the country, there has been a steady rate of violence there and on Saturday a roadside bomb exploded next to an Iraqi military convoy, killing one soldier and injuring two others. US commanders have expressed concern that Iraqi forces may not be ready to shoulder the full burden of security in Mosul, but the Iraqi government has said the deadline is "non-extendable." Iraqi Vice President Adil Abdul-Mahdi told The Associated Press at an international economic conference in Jordan that there was a degree of Iraqi disquiet about the imminent US pullout. "We're nervous about the United States leaving Iraq, but this is a challenge we have to take," he said at the World Economic Forum meeting. President Barack Obama has said he plans to end American combat operations in Iraq by Aug. 31, 2010, leaving a contingency force of up to 50,000 to train and advise the Iraqi security forces. "We're confident of our forces and I think we can win that challenge," said Abdul-Mahdi, one of Iraq's two vice presidents. Meanwhile, sporadic violence continued in Baghdad, with a mortar round crashing into a house in the eastern part of the city, killing a 2-year-old child and wounding three others, said an Iraqi security official. The official said the actual target was unclear, but there is a US base half a mile (one kilometer) away. Two policemen were also killed west of the city by a roadside bomb that went off near their patrol, said another security official. Both officials spoke on condition of anonymity because they were not authorized to the speak to the press. Also Saturday, a US soldier died in combat in southern Iraq, according to the US military, which did not provide further details. It was the second death in the normally quiet south in a week, following the killing of a 60-year-old US army major by a roadside bomb. A helicopter spraying date palms for the Iraqi Agriculture Ministry crashed Saturday when it became entangled in high tension power lines in Rashidiya, north of the capital, said Samir Al-Obiedi, the ministry's media director. The pilot and a female agricultural engineer heading the ministry's crop-dusting program were killed.