Right-wing Muslim groups have rallied their base against any move to dilute the laws after the sentencing of a Christian woman to death for blasphemy attracted local and international condemnation. Prominent among the critics was Gov. Salman Taseer, who was gunned down by a guard last week who later told media he was motivated by Taseer's stance on the laws.
Around 1,000 protesters gathered near the house of the confessed killer, Mumtaz Qadri, in Rawalpindi city close to the capital, Islamabad, carrying banners that saluted him. Elsewhere, protesters took to the streets in Karachi and two other cities in support of the laws and against the remarks by the pope last week.
"Pope Benedict's statement is an attack on the hearts of Muslims," read one placard carried by the protesters.
Last week, some 40,000 people protested in Karachi in support of Qadari, shocking many liberal Pakistanis and raising concern about growing extremism in the country.
The government, which is struggling against al-Qaida and Taliban militants, has since stated it has no plan to amend the blasphemy laws. Analysts say the government is too weak to pick a fight with Islamist forces, which are able to rally thousands of people on the streets even though their political parties only have a few seats in parliament.
Benedict spoke out against the blasphemy laws Monday, saying they should be repealed because they were used as a pretext for violence against non-Muslims.
Also in Karachi, police said 10 people had been killed over the last 24 hours in what appears to be a fresh round of ethnic and political violence. Police officer Rafiq Gul said the slayings were "target killings," the phrase used by authorities to describe political or ethnically motivated murders.
Karachi, a port city of about 16 million, has a long history of political, ethnic and religious strife. Last year bouts of similar violence claimed the lives of scores of people, weakening the central government as well as the already anemic economy.
Meanwhile, gunmen stormed the house of a female police officer, killing her and four relatives, in an unusual attack in northwest Pakistan, police said Friday. The attack happened Thursday night in Hangu, a district just outside the tribal belt bordering Afghanistan.
Islamist militants and criminals are active in the area, and they frequently attack male security officials. But women rarely hold such positions in the conservative region and it appeared to be the first time one was directly targeted.
The motive, however, was unclear, police officer Umar Draz Khan said.
The 50-year-old female officer, Shamshad Begum, had been in the force for several years. Her latest assignment was searching women at checkpoints. Her two sons, daughter and a daughter-in-law were also killed, Khan said.
Also Friday, Afghan officials denied Pakistani claims that Afghan troops carried out a cross-border mortar attack that killed eight people in a Pakistani tribal region. NATO said its initial reports indicated foreign troops played no role in Thursday's attack, either.