The governor of Pakistan's Punjab province was assassinated by his own security guard Tuesday, according to Interior Minister Rehman Malik, apparently because he spoke out against the country's controversial blasphemy law.

The security guard was arrested, Malik said. The shooting occurred at Islamabad's Kohsar Market, which is frequented by foreigners.

The guard, Malik Mumtaz Hussain Qadri, confessed to assassinating Taseer because "he did blasphemy of the Prophet Mohammed," said Naeem Iqbal, spokesman for Islamabad police. Qadri told police Taseer had described the blasphemy law as "the black laws."

The blasphemy law makes it a crime punishable by death to insult Islam, the Quran or the Prophet Mohammed.

After the shooting, Qadri immediately surrendered to authorities, the Associated Press of Pakistan reported, citing Malik.