( AFP ) - Pakistan on Wednesday considered emergency measures to deal with a wave of Islamist violence that erupted with last week's Red Mosque raid, after a new suicide attack in the capital killed 17 people.
Tuesday's blast targeting a rally by the country's ousted top judge was the fifth suicide bombing since the army assault on militants at the Islamabad mosque, which triggered calls for holy war against President Pervez Musharraf.
The explosion simultaneously brought to a head the two major crises facing the US-backed military ruler -- his March 9 suspension of chief justice Iftikhar Muhammad Chaudhry and the sudden upsurge of extremism in the country.
Washington meanwhile piled pressure on Musharraf to launch a military offensive against militants hiding in Pakistan's Al-Qaeda-infested tribal belt, where two blasts early Wednesday injured another seven people.
"Imposing a state of emergency is one of the possibilities with the government but it is not being contemplated at the moment," Deputy Information Minister Tariq Azeem told AFP.
Security has been tightened across the country, especially in Islamabad, and the minister said the government was "determined to fight extremism and terrorism and is using all resources to crush it."
He said the spate of bloodshed was believed to be linked to the siege and storming of the pro-Taliban Red Mosque, which left over 100 people dead, and to the redeployment of troops in the region along the border with Afghanistan.
"The militants are desperate and turning to suicide bombings," Azeem said.
Officials said any decision on declaring an emergency must be taken by the Pakistani cabinet, which was to meet later Wednesday.
Analysts say such a move would delay elections expected later this year, boosting Musharraf's aims to defy the constitution and remain in power as both president and army chief.
Investigators probing the Islamabad blast found parts of a badly mutilated head believed to belong to the suicide bomber and were trying to trace his identity, the city's deputy inspector general of police Shahid Nadeem said.
The death toll from the blast rose to 17 overnight after two people died in hospital, interior ministry spokesman Brigadier Javed Cheema said.
Speculation swirled over who was behind the killings.
Intelligence officials said they had intercepted telephone calls during the siege of the Red Mosque between its rebel cleric Abdul Rashid Ghazi and a top Taliban leader in the tribal belt, Baitullah Mahsud.
Mahsud, who was blamed for orchestrating a string of suicide attacks earlier this year, told Ghazi that "if he is killed his blood will not be wasted", the officials said. Ghazi was shot dead in the raid on the mosque on July 10.
Exiled former premier Benazir Bhutto -- said to be seeking an alliance with Musharraf -- agreed the blast was likely a militant backlash as it mainly hit workers from her secular Pakistan People's Party.
But many of the hundreds of lawyers at the event saw the hand of Pakistan's shadowy intelligence services in the attack.
Musharraf suspended Chaudhry on abuse of power charges, but Chaudhry's supporters say he was ousted because he could have threatened the president's continued grip on power.
The Supreme Court is expected to rule on the case this week.
General Musharraf -- who took power in a bloodless coup eight years ago -- has been under fire both from pro-democracy groups who demand fair elections and hardliners who would turn Pakistan into a strict Islamic state.
Meanwhile a US intelligence report warned on Tuesday that Al-Qaeda has regrouped in its Pakistani "safe haven" in the tribal areas and is determined to inflict mass casualties through new attacks on the United States.
Richard Boucher, the US assistant secretary of state for South and Central Asian affairs, said in Washington on Tuesday that "some military action is necessary, and will probably have to be taken."
Violence has shaken the frontier region where militant leaders Sunday scrapped a 10-month peace deal and threatened "guerrilla war," while rebuffing government attempts to save the accord.
Six civilians and a soldier were wounded Wednesday in a roadside bomb blast in the tribal area of North Waziristan, the epicentre of much of the militant problem in northwest Pakistan.
Separately a landmine exploded overnight outside the Miranshah home of a former federal sports minister, destroying his front gate but causing no casualties, officials said.