Islamist extremists frequently attack Muslims as well religious minorities to sow fear and undermine confidence in the Pakistani government.

As anguished friends and relatives of Bhatti, a 42—year—old Roman Catholic, prepared to bury him in his home village of Khushpur on Friday, mourners packed an Islamabad church in the morning to pay their respects.

There, Prime Minister Yousuf Raza Gilani praised the man many described as gentle, humble and devoted to helping Pakistan’s downtrodden religious minorities.

“People like him, they are very rare,” Mr. Gilani told the overflowing crowd. “All the minorities have lost a great leader. I assure you, we will try our utmost to bring the culprits to justice.”

The prime minister did not specifically mention Islamist extremists who have waged a war on the country, though he has issued statements denouncing them in recent days. Mr. Gilani also avoided mentioning the blasphemy laws, which rights groups have long deplored as vague and misused to persecute minorities.

Christians are the largest religious minority in Pakistan, where 95 percent of the country’s 180 million people are Muslim. They often are the victims of discrimination and persecution, and they typically live in poor parts of towns and do low—skilled, badly paid jobs.