The US commander of international troops in Afghanistan on Tuesday ordered an investigation into the improper disposal of a large number of Islamic religious material, including copies of the Holy Quran, at an American air base north of Kabul. More than 60 Afghans staged a morning demonstration outside the sprawling military installation to protest what they said was the burning ofholy books. \"We are thoroughly investigating the incident and are taking steps to ensure this does not ever happen again,\" US General John Allen, the top commander of US and Nato troops in Afghanistan, said in a statement. \"I assure you, I promise you, this was not intentional in any way.\" Allen said he received a report during the night that people working for the military coalition improperly disposed of the religious material. He did not elaborate. \"When we learned of these actions, we immediately intervened and stopped them,\" Allen said. \"The materials recovered will be properly handled by appropriate religious authorities.\" Ahmad Kabir, the chief of Bagram district of Parwan province where the base is located, said the demonstrators were all people who work inside the base and that some claimed they had seen pieces of a Holy Quran that was burned inside the base. \"I haven\'t seen it myself and we are talking to them and are investigating to see if is true,\" Kabir said. \"The protesters are nervous over these claims of the holy book being burned.\" Kabir called for calm. \"We will investigate and we are asking everyone to calm down and relax,\" he said, adding that the incident was being probed by local Afghan and police officials and the local provincial council. Police said a similar protest on Tuesday just east of Kabul ended peacefully. In a separate incident, gunmen in Afghan police uniforms opened fire on Nato troops on Monday in southern Afghanistan, killing an Albanian soldier, officials said. A second Albanian and another international soldier were wounded, they said. Eleven suspected policemen were arrested. The shooting appears to be the latest in a growing number of turncoat attacks that have raised questions about the vetting of Afghan recruits and threatened the international military commitment to Afghanistan. Last month, France suspended its training program and threatened to withdraw its forces a year ahead of schedule after an Afghan soldier shot and killed four French soldiers on a base in eastern Afghanistan. Monday\'s shooting occurred in the village of Robat, in Kandahar province\'s Spin Boldak district which borders Pakistan, said Kandahar police chief Abdul Raziq. The troops had gone there for a meeting about opening two schools and a health center, the Albanian defence ministry said. The soldiers “found themselves attacked by a group of persons wearing uniforms of the Afghan police,” Brig. Gen. Viktor Berdo, the head of Albanian land forces, told reporters in the country\'s capital Tirana. The attackers opened fire with five assault rifles and one light machine gun, the Albanian Defence Ministry said. One Albanian, a captain, died later in a hospital in the provincial capital of Kandahar city. Albanian officials initially said a corporal also was killed, but later clarified that the soldier was in a coma, adding “there is still hope of improvement.” Another international soldier was wounded, the ministry said, without providing a nationality. The Albanian ministry said the remaining soldiers “arrested 11 Afghan policemen who opened fire.” Albanian President Bamir Topi denounced the attack as a “grave terrorist act” and called for the punishment of those responsible. It was the first time any of Albania\'s soldiers have been killed in Afghanistan. The country has 265 troops in the country. There have been more than 45 of these insider attacks in Afghanistan since 2007, more than 75 per cent of those in the last two years, according to Pentagon data. Monday\'s attack on Nato forces came after a suicide car bomber struck a police station in the provincial capital of Kandahar city. The attacker drove a Toyota Corolla up to the checkpoint outside of the Kandahar police station and detonated his explosives, Raziq said. One police officer was killed and four people were wounded in the explosion two police officers and two civilians, he added. A civilian compound nearby was also destroyed, according to a statement from the Kandahar government\'s media office. No one immediately claimed responsibility for the attack, but it fit the pattern of Taliban assaults, which usually focus on government installations or security forces. Also Monday, three Italian soldiers were killed in a vehicle accident in the west of the country. Italian President Giorgio Napolitano issued a condolence message expressing his “deep emotion” over the news of the deaths in Herat province. The Italian soldiers were in a convoy going to survey a canal project in Herat\'s Shindand district when their vehicle crashed into a canal, said provincial police spokesman Rauf Ahmadi. The Italian news agency ANSA said that the soldiers\' armored vehicle overturned while crossing a stream.