KABUL — Top US military officer General Martin Dempsey arrived in Afghanistan on an unannounced visit Saturday to assess the level of training the US will need to provide Afghan forces after NATO withdraws in 2014, an official said. Meanwhile, a suicide bomber targeted a provincial governor's convoy Saturday near a hospital in southern Afghanistan, killing a doctor. An estimated 100,000 foreign troops have been fighting the Taliban for the past 11 years and are due to leave Afghanistan by December 31, 2014 to be replaced by a smaller contingent to train and advise their local counterparts. General Dempsey, chairman of the Joint Chiefs of Staff, will “assess the level of training that US/ISAF will provide to Afghan security forces”, a military official said. Afghan security forces, numbering around 330,000, are widely seen as ill-equipped, under-trained, and even corrupt. Lots of Afghans fear they will fail to contain the growing insurgency once the international troops leave. The US army still has 68,000 troops on the ground in April 2013. Speculations on the size of its force post-2014 range from 6000 to 20,000 soldiers. 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. Gov. Mohammad Ashraf Nasery, who escaped the assassination attempt on Saturday, said a car bomb exploded as his convoy was passing the hospital en route to an event at a nearby school in Qalat, the capital of Zabul province. He said the doctor was killed, and two of his bodyguards and a student from the school were wounded. “I'm safe and healthy,” he told The Associated Press in a telephone call. “The target was my vehicle, but I survived.” Zabul is located next to Kandahar, the birthplace of the Taliban, and shares a volatile border with Pakistan. Provincial police chief Gen. Ghulam Sakhi Rooghlawanay said earlier that the attacker was a suicide bomber on foot who detonated his explosives as the governor was on his way to visit the hospital. The UN has expressed concern about the spike in targeted killings as the Afghan government works to assert control beyond its seat in Kabul.— Agencies