The leader of the World Council of Churches is urging Pakistan’s leaders to repeal controversial blasphemy laws critics say are being misused by extremists.

In a letter to Pakistani President Asif Ali Zardari and Prime Minister Syed Yousaf Raza Gilani, the Rev Dr Olav Fykse Tveit recalled his organisation’s past calls of concern over Pakistan’s blasphemy laws, which he said are “fraught with danger that can be abused by extremist groups when dealing with religious minorities”.

“It has been proven in the past that the charges of Blasphemy law appear to be arbitrarily applied and at times founded on malicious accusations against individuals and groups,” Tveit wrote in his letter on Friday.

“The WCC has expressed its concern in the past and many others stated the same that the introduction of Blasphemy Law in Pakistan is inimical to and destructive of the harmony and well-being of people who live together in a religiously plural society,” the WCC general secretary continued.

Under Pakistan’s blasphemy laws, violators can be sentenced to 10 years in prison for insulting another person's religious feelings. Defiling, damaging, or desecrating the Koran carries a life sentence while blaspheming against Islam or its prophets can be punishable by death.

Rights organisations say some individuals have brought charges under these laws to settle personal scores or to intimidate vulnerable Muslims, sectarian opponents, and religious minorities. Furthermore, those accused of blasphemy and their families or religious communities are occasionally attacked and threatened with death by religious extremists – even after they are acquitted of blasphemy charges.

“The misuse of the Blasphemy Law in Pakistan has led to physical violence, damage, destruction of properties and loss of life within the innocent Christian minority over the years,” Tveit noted in his letter. “This is a violation of the fundamental rights guaranteed by Article 36 of the Constitution of Pakistan.”

Tveit’s letter comes four days after two Christians accused of blasphemy in Pakistan were killed as they left a courthouse.

On Monday, masked gunmen opened fire on Pastor Rashid Emmanuel and his brother, Sajid Emmanuel, as police were transporting them from the court in Faisalabad to jail.

According to Compass Direct News, the brothers were expected to be exonerated soon after handwriting experts on July 14 notified police that signatures on papers denigrating Islam’s Prophet Muhammad did not match those of the accused.

Reports said that police had brought the accused to the court of law to obtain their remand.

Tveit said he received news of the murders “with great dismay”. He appealed to Pakistan’s leaders “to ensure immediate and necessary actions to bring to justice those who are responsible for the killing” of the Christian brothers.

“We also urge Your Excellency to initiate measures towards the repeal of the Blasphemy Laws and to secure the rights and dignity of all individuals in Pakistan society,” Tveit said.

Islam is the state religion in Pakistan and the constitution requires that laws be consistent with Islam. Muslims make up an estimated 97 per cent of Pakistan's 180 million people.