Twelve Afghan civilians were killed Sunday during a major US-led offensive against Taliban in southern Afghanistan, as commanders said booby traps and snipers were slowing progress.
NATO claimed responsibility for the deaths, which it said happened when two rockets missed their target and landed on a compound as troops came under fire in the Nad Ali district of Helmand province.
The deaths were the first reported civilian casualties since the pre-dawn launch on Saturday of Operation Mushtarak, which is testing a new US-led war strategy aimed at re-establishing government control over the area.
US Marines are leading 15,000 US, NATO and Afghan troops in the assault focused on Marjah town, in the central Helmand River valley, which has been controlled by Taliban and drug traffickers for years.
Objectives of anti-Taliban assault in Afghanistan
The announcement of the civilian deaths -- and an apology by the commander of foreign troops in Afghanistan, US General Stanley McChrystal -- came as US President Barack Obama's national security adviser James Jones said the offensive was going well after the first 24 hours of fighting.
"It's an important moment in time because this is the first time we put together all of the elements of the president's new strategy," Jones, who visited Afghanistan and Pakistan last week, told CNN.
Jones's assessment was echoed by British military spokesman Major General Gordon Messenger, who told journalists at a briefing in London that British commanders were "very much of the view this has gone according to plan".
The next stage of the operation to consolidate the area had begun, Messenger said, with British troops constructing bridges and building bases.
Troops have also provided security to allow hundreds of Afghan elders to attend two shuras, or tribal gatherings, in a town which was formerly the local seat of Taliban government.
Mushtarak ("together" in Dari) is NATO's biggest operation against the Taliban since Obama announced his new surge policy, with another 30,000 US troops and 10,000 from NATO being deployed to the Afghanistan this year.
NATO's International Security Assistance Force (ISAF) confirmed the deaths of two soldiers -- one British and one American -- in the assault.
It later announced a third ISAF death in southern Afghanistan but did not say if it was related to the operation.
President Hamid Karzai's office said he had ordered an investigation into the civilian deaths, which happened less than 24 hours after he warned troops to take all precautions to protect residents of the region.
NATO and Afghan commanders said good progress in their mission was being slowed by huge numbers of IEDs, or homemade bombs, planted in and around towns and villages as fleeing militants had booby trapped areas as they went.
Afghan and British soldiers sweeping through villages in the area surrounding Marjah found IEDs buried by roadsides, in fields, hanging from trees, even embedded in walls, an Afghan army colonel said.
"We found IEDs all over the place," Colonel Shirin Shah, commander of 1 Brigade, 115 Corps Helmand province, told AFP.
"In the past 48 hours since we got here we have found and defused around 80 IEDs," he said, speaking in Haji Qari Saheb village.
IEDs -- crude, cheap and easily made bombs often detonated remotely -- are the main killer of foreign and Afghan forces fighting the Taliban because they can be almost impossible to detect.
Afghan Army General Shair Mohammad Zazai told reporters in the provincial capital Lashkar Gah that 27 armed militants had been killed, up from Saturday's toll of 20.
The United Nations said an estimated 900 Marjah families were being sheltered after fleeing ahead of the assault, and called on combatants to respect aid workers.
"The affected population must be assured of unobstructed access to basic services," Robert Watkins, of the UN's Office for the Coordination of Humanitarian Affairs, was quoted as saying in a communique.
In a statement released by the Taliban, a commander named Mullah Abdul Rezaq Akhund was quoted condemning the offensive as a face-saving public relations stunt "to give some prestige to the defeated and failed military commander General Stanley McChrystal".
