(Adds 14 wounded, background) KHOST, Afghanistan, Jan 23 (Reuters) - A suicide bomber set off explosives outside a NATO base in southeast Afghanistan on Tuesday killing 10 Afghans, the provincial governor said. Those killed were labourers, waiting at a checkpoint to get in to the base to work, said Khost provincial governor Arsala Jamal. "This was carried out by the enemies of our country," Jamal said. He said 14 people were wounded. A NATO spokeswoman said no NATO troops were hurt. It was not immediately clear if the bomber was on foot or in a vehicle. Suicide bombings were almost unknown in Afghanistan until 2005 but the number of attacks surged to 139 last year, according to U.S. military figures, as part of a sharply intensified Taliban insurgency. There have been several suicide attacks this year.
