PESHAWAR - At least 17 persons including 13 personnel of the security forces were killed when the US-led coalition forces attacked the border checkpost Chopana in Mohmand Agency on the night between Tuesday and Wednesday. The killed persons besides others included a Major of Mohmand Rifles of Frontier Corps and five alleged militants. Meanwhile, Tehrik Taliban Pakistan claimed shooting down a NATO helicopter and making hostages seven personnel of the Afghan National Army in retaliation. Amidst conflicting reports regarding the clashes, the Army high-ups have confirmed NATO forces attack and denounced it in strong words. The Pakistani officials claimed that coalition forces, camping across the border in Afghanistan in connection with their assignments in the ongoing war on terror, attacked the security forces at Chopana in border areas of Mohmand Agency. They claimed that the NATO forces used modern and heavy weapons during the attack, causing heavy human casualties and property destruction. However, the independent sources informed that clashes erupted in the area late Tuesday evening when the alleged militants ambushed a part of the Afghan National Army. In fact, the Afghan National Army occupied the Chopana Security Forces checkpost on Tuesday noon. Later on they were convinced by their counterparts from Mohmand Rifles to return. However, upon return the Afghan National Army was ambushed by the militants and clashes erupted between the two sides. In the meantime, the NATO forces along with helicopters rushed to the site for rescuing the Afghan National Army. The gunship helicopters bombed the area and later on attacked the militants with artillery and mortar shells. The security forces checkpost at Chopana became the main target, causing loss of around 13 personnel of the security forces and injuries to several others. During the attack around 50 personnel of the security forces were present in the post. However, some officers in Peshawar confirmed the killing of 11 personnel of security forces and seven tribesmen in the attack. Independent sources informed that besides four civilians, five alleged militants calling them Taliban were also killed. Taliban have confirmed the killing of five but the independent sources believe that eight Taliban were killed in the clashes. Later bodies of 13 persons were airlifted from the site to Ghalanai headquarters of Mohmand Agency by a helicopter. Similarly nine injured were also airlifted from Mohmand Agency to Peshawar and admitted in hospital. Besides Maj Akbar other killed persons were identified as Naib Sobedar Salah Ud Din and Saif Ullah, soldiers Zartaj, Jalat Khan, Akhtar Bagh, Gulistan, Noor Elahi, Rashid and Salim. Amongst the killed personnel Maj Akbar belonged to Punjab whereas Naib Sobedar Salah Ud Din was from Kohat. Zartaj was from Adezai Charsada and Jalat Khan was from Dir. The remaining Naib Sobedar Saif Ullah, Akhtar Bagh, Gulistan, Salim,  Noor Elahi and Rashid belonged to Khyber Agency. On the other hand, Tehrik Taliban Pakistan spokesman Maulvi Omar has claimed that their Mujahideen have shot down a NATO forces helicopter, which was on its return flight after attacking the security forces checkpost. He also claimed making hostages seven personnel of the Afghan National Army. The Afghan army men, he said, were in custody of Taliban and could be paraded to media at appropriate time. It may be mentioned here that Afghan government was having its claim on Chopana checkpost since long. The Afghan government had constructed and occupied the checkpost in 2003 but later on the Afghan troops vacated and abandoned it. Meanwhile, Namaz-e-Janaza of the ten soldiers of Frontier Corps was offered at the Panda Ground in Peshawar Cantt on Wednesday afternoon. The Namaz-e-Janaza was also attended by Governor Owais Ahmed Ghani, and Chief Minister Amir Haider Khan Hoti, Inspector General of Frontier Corps Maj Gen Muhammad Alam Khattak and a large number of officers and jawans of the force. Later, the dead bodies of the deceased were sent to their native areas. Agencies add: Pakistan's military condemned a "cowardly" US airstrike, saying it could jeopardise cooperation in the 'war on terror'. It heightened tensions between Pakistan and the US-led coalition in Afghanistan, which recently warned that the new government's decision to hold peace talks with militants could increase cross-border infiltration. An army spokesman "condemned this completely unprovoked and cowardly act" and blamed the coalition for the "aerial attack" that destroyed a paramilitary post in the Mohmand tribal region, a statement said. "The incident had hit at the very basis of cooperation and sacrifice with which Pakistani soldiers are supporting the coalition in the war against terror," it quoted the spokesman as saying. Pakistan had lodged a strong protest with the coalition, it said. Heavily armed local tribesmen brandishing rocket launchers and Kalashnikov rifles gathered near the checkpost in the mountainous Gora Prai area to show their support after the attack, residents said. Pakistani security officials said the deaths came after Afghan troops crossed the porous frontier and tried to occupy the strategic Pakistani post in the troubled tribal belt, which borders eastern Afghanistan. Pakistani troops repulsed the Afghan soldiers and the coalition then bombed the area. Coalition aircraft also killed around 15 Taliban militants about a kilometre away, the officials said. On the other hand, two US drones were seen flying over the Pak-Afghan border into the area of North and South Waziristan creating panic among the locals. In Kabul, the US-led coalition in Afghanistan admitted carrying out an airstrike in Pakistan Wednesday but said it targeted militants, after Islamabad accused the force of killing 11 Pakistani soldiers. The coalition said during an operation in Afghanistan's eastern Kunar province it informed the Pakistani army it was coming under fire from "anti-Afghan" forces in a wooded area near a checkpoint in Pakistani territory. Unmanned drone aircraft identified the militants and "in self-defence" the coalition fired artillery rounds and then used close-air support "until the threat was eliminated." The statement said an investigation was still ongoing but did not specifically refer to Pakistani allegations that the soldiers were killed in a coalition airstrike on the checkpoint in Pakistan's Mohmand tribal agency. Meanwhile, Islamabad on Wednesday summoned Washington's Ambassador to lodge a protest over the airstrike, state media said. Foreign Secretary Salman Bashir conveyed the "resentment from the government to the ambassador" Anne Patterson, the official Associated Press of Pakistan reported. Bashir told Patterson that "Pakistan strongly condemned the air attack on the Frontier Corps' border checkpost at Gora Prai in Mohmand Agency by the Coalition Forces based in Afghanistan," it said. "The attack was unprovoked and a gross violation of the international border between Pakistan and Afghanistan," he added. "The senseless use of airpower against a Pakistani border post by Coalition Forces is totally unacceptable. It constitutes a blatant and wilful negation of the huge sacrifices that Pakistan has made in its endeavour to combat terrorism." State run television quoted Senate leader Raza Rabbani as saying that Foreign Minister Shah Mehmood Qureshi will raise the issue during a meeting in Paris with US Secretary of State Condoleezza Rice.