Pope Benedict XVI has called on Pakistan to repeal its blasphemy laws, which can carry a death sentence for insulting the Prophet Muhammad.
He said the laws served as a pretext for acts of injustice and violence against religious minorities.
The Pope referred to Pakistani governor Salman Taseer, whose assassination last week was blamed on his support for changes to the blasphemy laws.
A bodyguard of Mr Taseer has confessed in court to his killing.
Malik Mumtaz Hussein Qadri told the Anti-Terrorism Court in Rawalpindi that he had acted alone in the attack.
The Pope made his remarks in a new year address to diplomats accredited to the Vatican.
"I once more encourage the leaders of that country [Pakistan] to take the necessary steps to abrogate that law," he said.
"The tragic murder of the governor of Punjab shows the urgent need to make progress in this direction," he added.
The Pope also condemned anti-Christian attacks in Egypt and Iraq, saying they showed "the urgent need for governments of the region to adopt... effective measures for the protection of religious minorities".
The BBC's David Willey in Rome says it was one of the Pope's most robust defences yet of religious freedom.