RAWALPINDI, Pakistan — Police blocked a suicide bomber who blew himself up near the office of President Musharraf today, killing seven people, officials said.

Meanwhile, more than 1,000 supporters of a former prime minister, Nawaz Sharif, marched on Pakistan’s Supreme Court in Islamabad as it prepared to hear arguments challenging his deportation last month by the Musharraf government.

The suicide bomber had walked up to a checkpoint in the city of Rawalpindi just a quarter-mile from Army House, the headquarters of the Pakistani army. General Musharraf, a key American ally who is also army chief, was safely inside at the time, his spokesman, Rashid Qureshi, said.

The attack could further heighten fears for Pakistan’s stability just as it prepares for crucial parliamentary elections and faces a growing threat from Islamic militants.

Police said three of their officers and four civilians were killed. Fourteen policemen and four civilians were wounded, he said.

“When police officers asked him to halt, the attacker got panicked. And as the police tried to capture him, he blew himself up,” a city police chief, Saud Aziz, said. “Our officers died to protect the citizens of Pakistan.”

Police said women and children aboard a passing minibus were also among the dead and wounded. Television footage showed schoolbags abandoned on the seats of the vehicle, whose windows were blown out.

While there was no claim of responsibility, Pakistan has been rocked by a string of suicide attacks mostly blamed on Islamic extremists battling security forces near the Afghan border.

A suicide bombing on the homecoming parade of a former prime minister, Benazir Bhutto, on October 18 in the southern city of Karachi killed more than 140 people. In Rawalpindi, a garrison city just south of the capital, two blasts on September 4 killed 25 people and wounded more than 60, many of them on a Defense Ministry bus.