Expanding their attacks on civilian targets, suspected militants killed 88 people when a car laden with explosives struck a volleyball tournament in a north-western Pakistan town which has a history of resisting the Taliban.
In a vivid demonstration of the militants' geographical reach and disregard for innocent life, the bomber drove on to the volleyball field, in a crowded district of the town of Lakki Marwat, detonating his device as young men competed in matches in front of several hundred spectators including the elderly, women and children.
It came as Pakistan's commercial hub, Karachi, ground to a halt as residents of the sprawling metropolis went on strike and protested against a horrific suicide bomb attack on a Shia mourning procession which killed 43 people earlier this week. The atrocity sparked arson attacks which consumed over 2,000 shops and took three days to douse.
Aside from last year's gun assault on the visiting Sri Lanka cricket team's tour bus in Lahore which killed eight people, attacks on sporting events in Pakistan are unusual. But the volleyball massacre was yet another example of how, despite their war with the Pakistan army, the militants are also increasingly focusing their operations on soft, civilian targets. At least 500 civilians across Pakistan have been killed since October. Before the Karachi attack on the Shia procession marking the holy month of Muharram, militants had blown up women's marketplaces in Peshawar and Lahore, and slain senior army officers in a Rawalpindi mosque moments after Friday prayers.
"The locality has been a hub of militants," Ayub Khan, Lakki Marwat's police chief, told reporters after the outrage. "Locals set up a militia and expelled the militants from this area. The attack seems to be reaction to their expulsion."
In recent years, a local Pashtun chief Anwar Kamal has mustered a thousands-strong militia that is fabled in the north-west and beyond for having rebuffed the Taliban's violent intrusions into Lakki Marwat, a wild and dusty town near the tribal areas.
"I told the Taliban in traditional language," Mr Kamal, distinguished by his fierce tones and Flashman-esque moustache, memorably told a British reporter once, "the next time I see a Talib on my land I am going to screw him as hard as I can."
The unrelenting wave of violence, which has even scarred long untroubled areas like Karachi and Pakistan-administered Kashmir in recent days, has left nerves jangling as confidence in the government rapidly depletes. Critics outspokenly blame President Asif Ali Zardari's weak and unpopular government for failing to advance a robust counterterrorism strategy in Pakistan's heartlands.
Citing the growing security threat, a spokesman for the United Nations in Pakistan said yesterday that a fifth of its staff will either relocate to "safer" parts of the country or leave. The decision comes after a series of attacks, most recently the bombing of the World Food Programme's Islamabad office, on personnel or premises used for some of its $1bn aid operations in Pakistan.
The wave of attacks also comes at a delicate moment for the embattled Mr Zardari. Since the Supreme Court struck down an amnesty clearing the President and his closest aides of corruption charges, pressure is steadily mounting on him to resign.
Principal blame for yesterday's and earlier attacks is being cast on the Pakistani Taliban, or its close affiliates. The militant group had claimed responsibility for the Karachi bombing, but since has dissociated itself from Monday's slaughter, in what may have been an attempt to evade public revulsion.
The scene of yesterday's sportsfield carnage is geographically near South Waziristan where the Pakistani army have been engaged in a major military offensive against the Pakistani Taliban.
Up to 20 nearby houses collapsed from the force of the blast and police said there was a possibility that dozens of people were trapped under the rubble.
According to Geo TV, members of a local "peace committee" which campaigns against the Taliban, were meeting at a nearby mosque in Lakki Marwat when the bombing happened.
* In Washington, Secretary of State Hillary Rodham Clinton condemned the attack.
"The United States will continue to stand with the people of Pakistan in their efforts to chart their own future free from fear and intimidation and will support their efforts to combat violent extremism and bolster democracy," she said in a statement.
In a statement issued in London, the Foreign Office said: "We condemn this horrific attack that has led to the needless loss of so many lives. Our thoughts are with the families of those who have lost their lives or who have been injured.
"We will continue to work with Pakistan to counter the threat that it faces from violent extremism.
"It is a threat that the international community must help Pakistan to tackle, in the interests both of Pakistan's people and of wider stability."