An Ahmadi Muslim doctor was shot dead this week in the latest attack on Islam's minority sect.

Chaudhry Khaliq Ahmad was killed in Karachi on Monday as he attended to his patients. His death follows a long line of similar incidents targetting Pakistan's Ahmadiyya community, which most Muslims hold to be blasphemous.

Another Ahmadi doctor, Hameed Ahmed, was shot dead outside his house in Darul Islam Colony in Attock on June 5. And on 25 May, Daud Ahmad was killed near his home in the same Karachi neighbourhood as Ahmad.

Pakistan's 1974 constitution declared Ahmadiyyas as "non-Mulim" and a subsequent ruling made it a criminal offence for them to be called Muslims.

A spokesman for the Ahmadiyya Muslim community in Pakistan, Salim ud Din, said: "I am shocked and saddened at the news of Chaudhry Khaliq Ahmad's murder. Words cannot describe the sorrow felt not only by myself, but all Ahmadis in Pakistan and throughout the world on account of this heinous act.

"It seems that there is no respite for Ahmadis even in the holy month of Ramadan. It appears that Ahmadis are being targeted in a clear and methodical way. The authorities need to act quickly to put an end to these indiscriminate murders."

Mervyn Thomas, chief executive of the religious persecution charity Christian Solidarity Worldwide (CSW), said: "CSW extends our heartfelt condolences to Mr Ahmad's family. We continue to be dismayed by the relentless targeting of the Ahmadiyya community in Pakistan and the environment of impunity which promulgates such attacks.

"We urge the police to apprehend and prosecute the perpetrators of this and other attacks. We also urge the government of Pakistan to amend discriminatory legislation and to take proactive steps to reduce the vulnerability of the Ahmadiyya community and other religious minorities in Pakistan."