Iqbal said 86 injured people were taken to hospitals. More than 50 were later released.
The bloodshed has heightened tensions with religious radicals calling for more revenge attacks on the government and troops moving into militant strongholds on the border with Afghanistan.
Tuesday's bombing underlined the antagonism as various parties sought to place blame.
Supporters of Iftikhar Mohammed Chaudhry, the former chief justice, have accused the government of being behind the mayhem.
An opposition party, believed to be considering joining a coalition government with Musharraf after year-end elections, said the attack was aimed at its loyalists.
In a sign of mourning and protest, the Pakistan Bar Council, the country's largest lawyers' association, has announced that its members would not engage in any court proceedings on Wednesday except for the chief justice's case.
Chaudhry, whose fight against Musharraf's effort to remove him has fueled opposition to the president extending his rule, was a few kilometres away when the attacker struck in the evening outside the Islamabad district court building.
'State of emergency'
Pervez Musharraf, the Pakistani president, condemned the blast as a "terrorist act," and officials said they were considering imposing a state of emergency on Wednesday.
"The government could take several steps and a state of emergency is a possibility," Tariq Azeem, the deputy information minister, told private television late on Tuesday after the attack.
Officials said any such decision must be taken by the Pakistani cabinet, which could meet on Wednesday.
Analysts say declaring an emergency 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.