Twin bomb attacks rocked Pakistan's capital Islamabad early Saturday, injuring two people, officials said.

The first blast took place around 2:00 am (2100 GMT) in an upmarket shopping area close to the city centre.

"It is not yet clear whether a suicide bomber was involved or not... both of the injured were watchmen," Chaudhry Hafiz Hussain, a senior police official, told AFP.

Local TV showed broken glass and branches strewn across the pavement.

Abdul Majeed, another police official, told AFP by telephone a separate bomb had gone off in another area of Islamabad around half an hour later, with no one hurt.

"The bomb disposal squad is examining the site to ascertain the nature of the second blast," he said.

The attacks were the first to strike the capital since an explosion tore through a fruit and vegetable market in April, killing at least 22 people.

Saturday's incident came after three days of air strikes by the Pakistani military against militant hideouts which killed at least 75 people, in apparent retaliation against insurgent strikes and against foreign fighters, according to a security official.

A month-long ceasefire between Pakistan and the Taliban, who have waged a seven-year insurgency, expired last month.