QUETTA, Pakistan - Pakistani Shi'ites agreed to bury those killed in the most recent sectarian bombing, ending four days of protests, after the government said on Tuesday it had arrested 170 suspects linked to the attack.

Saturday's bombing in the northwestern city of Quetta killed 85 people. In an echo of a protest last month after a similar attack left nearly 100 dead, grieving relatives refused to bury their kin in a powerful rebuke to a government they say has repeatedly failed to protect them.

A Shi'ite Muslim girl attends a protest against Saturday's bomb attack in Quetta's Shi'ite Muslim area, in Lahore Feb19, 2013. [Photo/Agencies]

On Tuesday, Shi'ite leaders called off the protest after Information Minister Qamar Zaman Kaira said four suspects had been killed and 170 people arrested within hours of the government announcing an operation against the militants.

"The operation will go on until all culprits are nabbed," Kaira said.

It was unclear how Pakistan's security forces were able to locate so many suspects in such a short period of time, or why they had not moved to do so before.

Pakistan has a poor record when it comes to prosecuting terrorism suspects. More than 60 percent of suspects brought before anti-terrorism courts in Punjab province were released in 2011, the most recent year for which data is available.

"All our demands have been met," said Shi'ite leader Amin Shaheedi. "The government has assured us that Quetta will be protected now and such incidents will not be repeated."

Interior Minister Rehman Malik said the government had also replaced the provincial police chief and offered to heavily fortify the Hazara Shi'ite enclave in Quetta. Those who come out risk being killed.

The Hazara are a distinctive ethnic group whose features and dialect make them easy targets for Sunni militants.

Protests in support of the Shi'ites in Quetta were also held in other cities across the country.

In the commercial hub of Karachi, protesters blocked the road to the airport. In the capital of Islamabad, protesters gathered outside the Supreme Court, where the powerful chief justice has opened hearings into the violence.

He is demanding reports from intelligence services on what they are doing to counter the threat from the Sunni sectarian group Lashkar-e-Jhangvi.

The LeJ claimed responsibility for both Saturday's bombing and one last month that claimed nearly 100 lives. Their campaign of bombings and assassinations of minority Shi'ites is a bid to destabilise nuclear-armed Pakistan and install a Sunni theocracy.

Sectarian attacks dramatically increased last year, killing more than 400 Shi'ites across Pakistan.

On Monday, a Shi'ite doctor famed for his charity work was shot dead along with his 11-year-old son as he took the boy to school in the eastern city of Lahore. Community leaders said it seemed to be a sectarian attack.

The violence has called into question whether the government can secure the country ahead of elections expected in May.