Police on Tuesday served a seven-day detention order on former Pakistani premier Benazir Bhutto [Images], hours before she was to lead a rally from Lahore [Images] to Islamabad to oppose the emergency imposed by President Pervez Musharraf [Images].

The detention order was issued by the home department of the Punjab government, which had earlier said all political rallies were banned under emergency regulations.

Police served the order at the house of Pakistan People's Party leader Latif Khosa, where Bhutto is currently staying.

Despite warnings from the government against going ahead with the long march, Bhutto had on Monday vowed to lead PPP workers across Punjab province over three days to mount pressure on Musharraf to end the emergency.

Punjab government officials said the measure had been taken for Bhutto's security as there were reports that suicide bombers had intended to target her.

Hundreds of policemen surrounded Khosa's home after midnight and prevented people and the media from approaching it.

Hundreds of PPP workers were also taken into custody across Punjab especially at places where Bhutto intended to address rallies during her march.