A Muslim extremist group claimed responsibility for threatening letters and phone calls which branded the three men as infidels, AsiaNews reported.
In an interview with Aid to the Church in Need, Bishop Coutts said he would not let himself be intimidated and that he would persist "with interreligious activities, in favor of social harmony and religious peace in the country."
The bishop added: "We have experienced the violence of certain extremist Muslim groups, a violence that in former times did not exist. This is for us a new phenomenon, which does not spring from the population in general, but from the promotion of this way of thinking within extremist groups."
Catholics account for 1.5 million of Pakistan's 165 million inhabitants.
Recent years have seen the development of positive relations between Christians and Muslims in Faisalabad, the third largest city of Pakistan, AsiaNews reported.