LAHORE, Pakistan (AP) -- Opposition leader Benazir Bhutto on Tuesday called on Pakistan's President Gen. Pervez Musharraf to resign and ruled out serving under him in a future government after she was placed under house arrest for the second time in five days.

With the political turmoil deepening, U.S. Deputy Secretary of State John Negroponte was headed to Pakistan and expected to reiterate Washington's calls for Musharraf to lift the state of emergency.
Musharraf's critics and chief international backers, including the United States, have said the restrictions imposed by the military leader — such as on independent media and rallies — would make it hard to hold a fair vote in upcoming parliamentary elections.
Bhutto was trapped in a padlocked house surrounded by thousands of riot police, trucks, tractors loaded with sand, and a row of metal barricades topped with barbed wire. She said it was now likely her Pakistan People's Party would boycott the January elections and ruled out serving another term as prime minister under Musharraf.
""I simply won't be able to believe anything he said to me,"" she told reporters by telephone from the house in Lahore where she was held to prevent her leading a protest procession.
Her comments appeared to bury hopes of the political rivals forming a pro-U.S. alliance against rising Islamic extremism. They had held months of talks that paved the way for Bhutto's return from exile last month to contest the parliamentary elections.
In the southern city of Karachi, Bhutto supporters fired on two police stations in a poor district where her party is popular, and police used tear gas to disperse demonstrators, senior police officer Fayyaz Khan said. No one was hurt. Bhutto told the private Geo TV network that Musharraf was a hurdle to democracy and must resign both as president and army chief.
She accused Musharraf of imposing effective martial law when he declared emergency rule on Nov. 3 — suspending citizens' rights and rounding up thousands of his opponents. Musharraf said the restrictions were needed to bolster the fight against the Taliban and al-Qaida.
Negroponte's trip to Pakistan was pre-planned and part of a regular strategic dialogue with Pakistan, a key ally in the U.S.-led war on terror, said U.S. Embassy spokeswoman Elizabeth Colton.
Authorities mounted a massive security operation to prevent Bhutto from leading a 175-mile procession to the capital, Islamabad to press for an end to the emergency. Officers detained scores of her supporters, including several lawmakers, who approached the barricades shouting slogans including ""Go Musharraf go!"" and ""Prime Minister Benazir!""
Bhutto's spokeswoman, Sherry Rehman, said the former prime minister was stuck in the house with a handful of top aides. She said Punjab's provincial government had attached the seven-day detention order as well as several padlocks to the front gate.
Aftab Cheema, chief of operations of Lahore city police, said Bhutto would not be allowed to leave the house, which was declared a ""sub-jail.""
Bhutto said once she was freed from detention, she would work to forge a broad alliance, including with Nawaz Sharif — a longtime rival and fellow former prime minister who shares her wish to end military rule.
Sharif was ousted by Musharraf in the 1999 coup that brought the general to power. He attempted to return to Pakistan in September but was immediately deported.
Speaking from exile in Saudi Arabia, Sharif said he believed the opposition was ""beginning to get together.""
Bhutto said she saw no prospect of achieving political power by cooperating with Musharraf's administration.
""Now we've come to the conclusion that even if we get power, it will just be a show of power. It won't be substantive power,"" Bhutto said.
""It seems unlikely that the People's Party will participate in the upcoming elections."" She described the vote as a ""stage-managed show"" to return the ruling party to power.