A suicide truck bomb attack on a joint NATO-Afghan army base in eastern Afghanistan on Wednesday caused several casualties to Afghan forces, the International Security Assistance Force said. Reports by Afghan officials of the number of soldiers wounded in the attack -- claimed by Taliban insurgents -- varied from 10 to 45, but there were no reports of any deaths. \"This morning a joint ISAF-ANSF (Afghan National Security Forces) combat outpost in Zurmat district in Paktiya province was attacked by insurgents using a vehicle-borne improvised explosive device and indirect fire,\" an ISAF spokesman told AFP. \"Early reports say the attack resulted in several ANSF casualties, but there is currently no reporting on ISAF casualties,\" he said. Deputy provincial governor Abdul Rahman Mangal told AFP: \"Around 45 army soldiers have been slightly wounded, mostly by broken glass, by the huge blast caused by a truck bomb at the gate.\" The Taliban said their fighters had infiltrated the base after the suicide attack and fighting was continuing -- claims denied by ISAF and Afghan officials. \"Our mujahideen armed with rockets, machine-guns, hand-grenades and suicide vests successfully infiltrated an American forces base in Zurmat district following a suicide car bomb attack,\" Taliban spokesman Zabiullah Mujahid told AFP. Afghan forces are taking on an increasing role in the war against the Taliban as NATO draws down its forces ahead of a pull-out of all combat troops at the end of 2014. So far this year the Afghan army and police have suffered an average of 535 casualties -- killed and wounded -- each month, ISAF said in a breakdown of the status of the 337,000-strong ANSF this week. In contrast, a total of 358 ISAF troops have been killed this year, according to the icasualties.com website. The ability of Afghan forces to take full responsibility for the fight against the Taliban is a key plank of NATO\'s exit strategy from the 11-year war and commanders regularly talk up the growing effectiveness of local troops. But many observers point to reports of indiscipline and lack of motivation among the Afghan forces as warning signs of problems ahead after they lose the military and logistical support of the huge NATO operation. While the Taliban\'s favourite tactic remains planting homemade bombs that kill indiscriminately, they have recently launched a number of direct attacks on military forces. On October 1, a suicide bomber attacked an Afghan-NATO foot patrol in the eastern city of Khost, killing at least 20 people, including three foreign troops and six Afghan police. And last month, Taliban insurgents launched a major attack on ISAF\'s Camp Bastion in Helmand province, destroying millions of dollars\' worth of aircraft and killing two US marines.