Chandigarh, March 21 : The National Security Act (NSA) has been invoked against pro-Khalistan self-styled radical Sikh preacher Amritpal Singh on Tuesday, who has been absconding since March 18, informed sources said on Tuesday. The police have launched massive search and cordon operations in the state against activists of Amritpal Singh's 'Waris Punjab De'. However, his supporters claimed that he was already in illegal police custody. Meanwhile, the Punjab police used massive force on Tuesday to physically remove hundreds of Sikh protesters, under the banner of Qaumi Insaaf Morcha, who had laid siege to Gurdwara Singh Shaheedan Chowk near Mohali after reports of the police detaining Waris Punjab De supporters. However, the police arrested a large number of supporters, who were armed with sharp-edged weapons. The Punjab government has extended curbs on internet and SMS services till March 23 noon in Tarn Taran, Ferozepur, Moga and Sangrur districts; Ajnala sub-division in Amritsar district; and areas in Mohali district. Chief Minister Bhagwant Mann said his government would take strict action against anyone who tried to disturb the state's peace and harmony. In his first reaction, Mann said he had received several calls from people praising his government. "People are telling me, you have done a good job. There should be peace and harmony in Punjab. In this matter, we will support you," he said in a video message. On Monday, the the police invoked the NSA against five people linked to the 'Waris Punjab De'. The stringent law has been invoked against Daljit Singh Kalsi, Bhagwant Singh, Gurmeet Singh and Pradhanmantri Bajeke and Harjit Singh, who have been shifted to the Dibrugarh Central Jail in Assam. Six FIRs have been registered and 114 people arrested against elements of Amritpal Singh's outfit. A team of the state police had chased Waris Punjab Da chief's convoy while he was on his way to Jalandhar on March 18 but he managed to escape on a motorcycle. /IANS