Militants today stormed into the offices of a US-based NGO in Mansehra area of northwest Pakistan, killing six persons, including two women. Police said, eight to 10 militants struck the premises early this morning, lobbing grenades and firing from their automatic weapons. Six persons were also injured in the incident. Law enforcement agencies sealed off the area and launched a search for the militants. North West Frontier Province Chief Minister Ameer Haider Khan Hoti condemned the incident and expressed sympathy over the loss of human lives. He said the government would compensate the affected families and reiterated his resolve to continue the fight against terrorism till the last militant is eliminated.