The ex-premier, who returned to Pakistan after more than eight years of self-imposed exile last month, earlier urged all Pakistanis to join a 270-km (170-mile) march from Lahore to Islamabad to demand that President Pervez Musharraf end the national state of emergency, set a concrete date for general elections, and step down as army chief.
Pakistani authorities, determined to prevent Bhutto from leading the rally, have her under house arrest for seven days. Several thousand police surrounded Bhutto's temporary residence in Lahore during the night, setting up barricades and barbed wire barriers, and blocking streets with trucks and trailers.
Several supporters protesting against the house arrest have been arrested outside the residence.
Last week, Bhutto was detained in her home in Islamabad ahead of a protest in Rawalpindi, near the capital against Musharaff's hard-line policies.
Musharraf declared a state of emergency in the country on November 3, citing a dangerous rise in militant activity.
According to Pakistan's Interior Ministry, about 670 people in Pakistan have been killed and over 1,800 injured in a total of 157 terrorist attacks this year.
The president banned the Supreme Court from overturning the emergency order, blocked non-state TV broadcasts, and restricted freedom of movement in the country, measures which all have been widely condemned by the international community.
Bhutto called the imposed emergency rule "unconstitutional," and pledged to continue the struggle for democratic reform in the country.
"I have returned to Pakistan to fight against extremism and for democracy," she said last week.
Benazir Bhutto, the leader of the Pakistan People's Party (PPP), has served as Pakistan's prime minister on two separate occasions. However, both her previous governments were brought down amid corruption allegations and she went into self-imposed exile in 1999. She has dismissed the corruption allegations against her as politically motivated.
