RAWALPINDI: Chief of the Army Staff (COAS)General Raheel Sharif Tuesday visited the Police Training Centre (PTC)Quetta and met police officials, army and FC troops, who carried out an operation last night to clear area, neutralise and eliminate the terrorists attacking the centre. The COAS appreciated the morale, courage and determination of security forces personnel for preventing further damage and saving many lives, said an ISPR press release.