The late morning explosions occurred within a two-minute span over several kilometres in the centre of the capital. Three blasts occurred near the Pakistani government buildings, about half a kilometre from Parliament and the adjacent President House.

The United States condemned the attacks and said it was still unclear who carried them out.

``We condemn these attacks. We are trying to find out more facts on injuries and at this point it is not clear who is responsible,'' National Security Council spokesman Mike Hammer said in Washington.

Local administration officials said that these rockets were fired from cars by unidentified people who then managed to flee.

Police said major damage was averted because all the explosions occurred at somedistance from the buildings in relatively uncrowded places.

The police officials said they managed to defuse a bomb near the Prime Minister's Secretariat in the heart of the city.

A US official said no Americans were hurt.

The blasts occurred two days before a UN deadline for the Taliban militia leadership in Afghanistan, Pakistan's neighbour, to turn over suspected terrorist Osama bin Laden for trial.

There has been little unrest in Pakistan since Pakistan strongman General Pervez Musharraf ousted Prime Minister Nawaz Sharif in a coup last month.In his first public statement after seizing power, Musharraf had signalled a shift in Pakistan's unequivocal support of the Taliban religious rulers, appearing to suggest that they share power with their opponents.

The Taliban, and supporters that include Muslim groups in Pakistan, have warned the United Nations against a plan to impose sanctions on Afghanistan to force bin Laden's handover.

On Wednesday, thousands of demonstrators in southern Afghanistanattacked UN offices with stones and bricks, burning US flags and effigies of President Bill Clinton to protest the pending sanctions.

Taliban officials apologised to the UN on Friday for the protest and for the damage caused to the UN offices.

Reclusive Taliban leader, Mullah Mohammad Omar, condemned the Islamabad explosions in a statement from the southern Afghan city of Khandahar, saying they were meant to damage relations with Pakistan and worsen dealings with the United States.

Police and paramilitary troops patrolled the streets and searched vehicles.

They erected barricades and pushed away onlookers, fearing more explosions.