Kandahar:
Six NATO personnel were killed on Saturday in two separate attacks in Afghanistan, officials said, in the deadliest day for foreign forces this year.
The strikes came as the top US military officer General Martin Dempsey arrived in the country on an unannounced visit and raise troubling questions about the Taliban's strength ahead of the coalition's withdrawal in 2014.
Three US soldiers and two American civilians were among the dead, a US security source said, while the State Department added Afghans were also killed.
In the southern province of Zabul, a Taliban car bomb struck a NATO convoy killing three troops and two civilian workers according to the International Security Assistance Force (ISAF).
An American citizen also died in "an insurgent attack" in eastern Afghanistan, a statement from US-forces Afghanistan said without giving any details.
Ashraf Naseri, the provincial governor of Zabul, told AFP he was on his way to attend an official function in the city of Qalat when he heard the blast.
"One doctor and one civilian were killed and two of my body guards have been injured," he said.
An ISAF spokesman in Kabul confirmed the explosion was a car bomb targeting a military patrol, adding that there were also Afghan civilian casualties.
American and Romanian troops are based in the province, according to the ISAF website, but the force did not disclose the victims' nationalities in line with its policy.
"An explosive-packed car went off this morning in Qalat city as a NATO convoy was passing. We heard it has caused heavy casualties," another provincial official told AFP on condition of anonymity.
Saturday is the deadliest day for the coalition since July 8th, 2012, when two separate attacks killed seven soldiers, also in southern and eastern Afghanistan.
Taliban insurgents, who have been waging a tough insurgency since the toppling of their regime in 2001, claimed credit for the deadly strike on their website, adding it happened near a newly constructed hospital.
The insurgents, who usually exaggerate the number of victims they kill, said: "Thirteen invaders were killed and nine others wounded whereas one guard of the governor was also killed with two others suffering injuries."
The attack, which coincides with the start of the fighting season for the Taliban, comes as US-led coalition forces are winding down their operations ahead of a scheduled full withdrawal of 100,000 remaining troops in 2014.
General Dempsey, chairman of the Joint Chiefs of Staff, arrived in the country on Saturday to assess the level of training the US will need to provide Afghan forces following the withdrawal.
Last August, insurgents' rockets hit General Dempsey's plane as it was parked at the Bagram air field and wounded two maintenance crew, according to officials. Dempsey flew out of the country unharmed using another plane.
In another show of strength, Taliban gunmen Thursday killed 46 people at an Afghan court complex in Western Afghanistan in a bid to free insurgents standing trial moved ruthlessly from room to room, shooting everyone they found.
That attack in Farah, a province that borders Iran, was the deadliest for more than a year in Afghanistan.