Seven people including two women were killed on Wednesday when gunmen stormed a building used by a US-based charity in Mansehra. The gunmen attacked offices of World Vision near Oghi town, in Mansehra district of North West Frontier Province, police and the aid worker said. "Some armed people stormed the building of World Vision NGO. There was firing and also an explosion inside," police official Sajid Khan told media. "They opened fire and also exploded hand grenades," he said. The aid worker confirmed the attack and subsequent clashes. "Six staff from World Vision are dead, six are seriously injured. More information is coming. The staff are trapped in the office," one of the air worker talking to media said. There were reports of injuries among students of nearby schools after stampede among them. The building of the NGO has been completely collapsed and the blast formed a 14 feet craft on the site of the blast. Federal Interior Minster Rehman Malik has sought report from IG NWFP. President Asif Ali Zardari and Prime Minister Syed Yusuf Raza Gilani have strongly condemned the blast. In their separate message, the president and the prime minister said that the nation is united against terrorists and they would not be succeeded in their nefarious designs. They directed the authorities concerned to provide all possible medical facilities to injured. Other political leaders including Quaid PML-N Mian Muhammad Nawaz Sharif, Chief PTI Imran Khan, Quaid MQM Altaf Hussain, Amir JI Manawar Hassan have also condemned the blast. Newly elected member of National Assembly Laiq Muhammad Khan and other local political leaders have hinted the involvement of foreign hand in Mansehra blast for paving the way of operation in the area.