IMPHAL, March 23: Patrolling and frisking by police and security forces have been intensified in and around Christian missionary schools in the state's valley areas. This was announced by Manipur Chief Minister Radhabinod Koijam today. Security for missionary schools was beefed up following threats from militants. A militant outfit had demanded Rs 40 lakh from eight Catholic missionary schools in Imphal. When the schools expressed their inability to pay the amount, the militants slapped a fine of Rs 2 crore on them and ordered them to close down. The matter was discussed in the Assembly today, when veteran Congress leader Rishang Keishing raised the issue during Question Hour. Giving his reply, the Chief Minister said the government was aware of the problem faced by missionary schools. Koijam said except for Don Bosco School, Langjing and St Joseph's School, Sangaiprou, all the other missionary schools were holding regular classes. The Chief Minister, who also holds the home portfolio, told the House that cases have been registered in connection with the extortion demands, which were being investigated. Many Catholic priests have been targeted by militants in Manipur over the past decade. Some of the priests have been killed while some of them have escaped attacks on their lives. Catholic missionaries have been protesting against such attacks by militants following extortion demands. The latest incident has forced many Catholic priests and teachers who are not local people to flee the state. In many cases, local Manipuri teachers have been entrusted by the Catholic missionaries to run the Imphal-based schools. The Chief Minister today said the government has not received any claims for the payment of ex gratia from the next of kin of priests killed or injured.