A Pakistani government minister Saturday offered a $100,000 reward for the death of the maker of the anti-Islam film produced in the US that sparked violent protests across the Muslim world.

Railways Minister Ghulam Ahmed Bilour invited members of the Talban and Al-Qaeda to take part in the 'noble deed', and said given the chance he would kill the film-maker with his own hands.

Bilour was speaking to reporters in the northwestern city of Peshawar a day after violent nationwide protests against the Innocence of Muslims film left 21 people dead and more than 200 injured.

"I announce today that this blasphemer who has abused the holy prophet, if somebody will kill him, I will give that person a prize of $100,000," Bilour said, urging others to shower the killer with cash and gold.

"I also invite Taliban and Al-Qaeda brothers to be partners in this noble deed," he said. "I also announce that if the government hands this person over to me, my heart says I will finish him with my own hands and then they can hang me."

Protests against the film, which mocks Islam and was made by extremist Christians, have erupted across the Muslim world, leading to more than 50 deaths since the first demonstrations on September 11.

The publication this week of cartoons mocking the Prophet Mohammed in a French satirical magazine has further stoked anger.

The producer of the film, Nakoula Basseley Nakoula, is reportedly a 55-year-old Egyptian Copt and convicted fraudster - out on parole - who lives in Los Angeles.

US media say Nakoula wrote and produced the film, using the pseudonym Sam Bacile before being identified. He was questioned overnight Friday by police before going into hiding with his family.

Thousands of Islamist activists in Pakistan staged demonstrations again Saturday but there was no repeat of the previous day's widespread violence.

More than 5,000 protesters marched towards the parliament in Islamabad, including hundreds of women, chanting 'We love our Holy Prophet' and 'Punishment for those who humiliated our Prophet'.

Some 1,500 people from the hardline Islamist Jamaat-ud-Dawa and Sunni religious groups rallied in front of the US consulate in the eastern city of Lahore, chanting 'The US deserves only one remedy - jihad, jihad'.

Hundreds gathered in the southwestern city of Quetta, calling for the makers of the film to be killed while scores in Peshawar, where six people died in Friday's protests, chanted anti-US slogans.

Religious groups rallied in the southern port city of Karachi, where 15 people were killed Friday, after the funerals of the demonstrators took place.

Witnesses estimated that nationwide rallies on Friday mobilised more than 45,000, mainly members of right-wing religious parties and supporters of banned terror groups, although the numbers were still small in a country of 180 million.

Police fought back with gunshots and tear gas as arsonists and looters attacked cinemas, banks, shops and restaurants in Karachi, where outbreaks of political and ethnically linked violence have killed hundreds this year.

Four more people died overnight from wounds they received during the protests, taking the number killed across Pakistan on Friday to 21, health department officials said.

The combined total of wounded in Karachi, Peshawar and in the capital Islamabad was 229.

Overall, 23 people have been killed in Pakistan during protests over the past week.