The US commander in Afghanistan on Saturday promised a full investigation after Pakistan said a NATO air strike killed at least 26 soldiers, sending his condolences over any troops who may have died. \"This incident has my highest personal attention and my commitment to thoroughly investigate it to determine the facts,\" said General John Allen, commander of NATO\'s International Security Assistance Force (ISAF). \"My most sincere and personal heartfelt condolences go out to the families and loved ones of any members of Pakistan security forces who may have been killed or injured,\" he added in a statement. US ambassador to Pakistan, Cameron Munter, also express regret and reiterated promises of an investigation. \"I regret the loss of life of any Pakistani servicemen and pledge that the United States will work closely with Pakistan to investigate this incident,\" he said in a short statement released by the American embassy. In September 2010, Pakistan shut the main land route for NATO supplies at Torkham for 11 days after accusing NATO of killing three Pakistani troops in another attack in its northwest. The border was reopened after the United States formally apologised. Pakistan says NATO strike kills 26 soldiers Pakistan on Saturday accused NATO of killing at least 26 soldiers in a blistering air strike, protesting in the strongest terms to the US and closing the main border for NATO supplies into Afghanistan. It was the deadliest NATO strike reported by Pakistan during the 10-year war in Afghanistan and looked set to inflame already extremely difficult US-Pakistani relations still reeling from the May killing of Osama Bin Laden. The US-led International Security Assistance Force (ISAF) said it was aware of an incident and seeking further information about what happened in Mohmand, part of Pakistan\'s lawless tribal belt branded an Al-Qaeda hub by Washington. Prime Minister Yousuf Raza Gilani \"strongly condemned\" the attack and \"on his directions the matter is being taken up by the foreign ministry, in the strongest terms, with NATO and the US\", the government announced. Gilani cut short a weekend visit to his home town to return to Islamabad for crisis talks with President Asif Ali Zardari, army chief of staff General Ashfaq Kayani and Foreign Minister Hina Rabbani Khar, state TV reported. Pakistan\'s military earlier condemned the pre-dawn attack on the border post in Baizai district as \"unprovoked\" and \"indiscriminate\". \"The death toll is more than 20,\" a military official told AFP on condition of anonymity because he was not authorised to release the casualty figures to the media. Among the dead was a major. Pakistan halts NATO supplies crossing into Afghanistan Within hours of the strike, Pakistan stopped NATO supplies crossing the Torkham border into Afghanistan and Pakistan\'s acting ambassador in Washington had reportedly lodged a formal protest with the State Department. \"We have stopped NATO supplies after receiving orders from the federal government,\" said Mutahir Hussain, a senior administration official in Khyber tribal region, on the Afghan border. \"Supply trucks are being sent back to Peshawar,\" he told AFP.