Pakistani authorities placed opposition leader Benazir Bhutto under house arrest for the second time in four days to prevent her staging a grand procession on Tuesday to protest emergency rule, police said.

A seven-day detention order was issued by the government of Punjab province, where the former prime minister is staying at the house of a lawmaker from her party, Aftab Cheema, the chief of operations of Lahore city police, told The Associated Press.

"She has been detained and she won't be allowed to come out," Cheema said.

A conflict over the march between Bhutto and Musharraf could intensify the political crisis engulfing Pakistan and further cloud the prospect of the two leaders forming a U.S.-backed alliance against rising Islamic extremism.