At least 15,000 Shia Muslims took to the streets in southwest Pakistan on Monday in a second day of protests following a bombing that killed 89 people.

Relatives of the victims refused to bury their loved ones until the army takes action against the militants targeting the minority sect.

Meanwhile, militants wearing suicide vests and disguised as policemen attacked the office of a senior political official in northwest Pakistan, killing six people, police said.

'We will not bury our martyrs until our demands are fulfilled.'—Amin Shaheedi, Paskistani Shia leader

Pakistan has been besieged by militant attacks in recent years, many of them carried out by the Pakistani Taliban, who have been waging a bloody insurgency against the government. Radical Sunni militant groups have also increasingly targeted the country's Shia because they do not view them as real Muslims.

Many of these sectarian attacks have occurred in southwest Baluchistan province, which has the largest concentration of Shias in Pakistan. Many are Hazaras, an ethnic group that migrated from Afghanistan over a century ago.

Death toll climbs

The bomb that ripped through a produce market Saturday in Baluchistan's provincial capital of Quetta was the second mass-casualty attack targeting Shias in the city in a little over a month. A double bombing of a billiards hall in January killed 86 people.

The death toll from the most recent blast, which was caused by a bomb hidden in a water tank, rose to 89 on Monday after eight people died of their wounds, said Baluchistan's home secretary, Akbar Hussain Durrani.

Outrage over the attacks has grown in Pakistan, and protests were held in over a half dozen cities Monday in addition to Quetta. But it's unclear whether the demonstrations will spark action that will make the Shias any safer.

A Pakistani police officer grieves outside a hospital over the deaths of his colleagues killed in a bombing, in Peshawar, Pakistan on Monday. (Sohail Iqbal/Associated Press)

Rights groups have criticized the government for not doing enough to crack down on the attacks. They explain this apathy by pointing to past connections between the country's military and anti-Shia militants, and also allege the sectarian groups are seen as less of a threat than the Taliban because they are not targeting the state.

Despite this criticism, the Shias in Quetta see the Pakistani army as their only potential saviour and are demanding the generals be given control of the city. They blame the provincial government and police for failing to protect them and want the army to take targeted action against sectarian militant groups like Lashkar-e-Jhangvi, which claimed responsibility for both the recent bombings in the city.

"We will not bury our martyrs until our demands are fulfilled," a top Shia leader in the country, Amin Shaheedi, told reporters Monday at the site of the protest in Quetta.

Saumbal, the police officer, estimated that the crowd of protesters numbered at least 15,000. Some poured into the streets near the attack site carrying signs and chanting slogans against terrorism. Others remained inside a mosque beside the bodies of their relatives, which were covered with white sheets. One young girl wrote on her face, "Don't kill me. I am Shia."

Shootings further sectarian tensions

After the bombing in January that killed 86 people, Shias camped out in the street for four days alongside the coffins of their loved ones. Eventually the country's prime minister ordered a shake-up in the regional administration, putting the local governor in charge of the whole province. But the governor has expressed frustration, saying the recent bombing was the result of a failure of the provincial security and intelligence services.

Durrani, the home secretary, said the government has no plans to call in the army and will continue to rely on the 3,000 members of the paramilitary Frontier Corps who are deployed in Quetta, as well as the police.

The most significant protests outside Quetta on Monday occurred in Pakistan's largest city, Karachi, located on the country's southern coast. Hundreds of protesting Shias paralyzed key areas of the city by blocking major roads, including the one that leads to the airport.

Violence in Karachi risked exacerbating sectarian tensions. Gunmen opened fire on a restaurant in the city, killing two people, said police spokesman Imran Shaukat.

A spokesman for a Sunni extremist group, Ahle Sunnat Waljamaat, said two of its activists were killed in the attack. Members of the group clashed with police following the shooting, he said.

In the eastern city of Lahore, gunmen on a motorcycle shot to death a Shia doctor and his 12-year-old son, but it was unclear whether the attack was sectarian in nature, said senior police officer Malik Ovais.

Disguised militants kill police

The target of Monday's attack in the northwestern city of Peshawar was the office of the top political official for the Khyber tribal area, a major militant sanctuary in the country. The militants were disguised in the same type of uniform worn by the tribal policemen who protect the compound.

At least five militants attacked policemen protecting the compound with assault rifles and hand grenades, said Mian Iftikhar Hussain, information minister for surrounding Khyber Pakhtunkhwa province. Some managed to slip inside the compound, and two blew themselves up. Officials are trying to determine what happened to the other attackers, he said.

Six people were killed in the attack, including four tribal policemen and two civilians, said senior police officer Shafqat Malik. Thirteen people were wounded, including some who were inside an office that collapsed from the force of the explosions.