The two major parties in Pakistan's coalition government swept to victory in by-elections to fill 33 vacant seats in the national and provincial assemblies, an official said Friday. The party of former Prime Minister Nawaz Sharif, Pakistan Muslim League-N, won three out of five parliamentary seats in Thursday's vote, while its senior partner in the coalition government, Pakistan People's Party, won two. Polling was postponed for a sixth parliamentary seat in the eastern city of Lahore because of legal wrangling over whether Sharif was eligible to contest. Kanwar Mohammad Dilshad, secretary of Pakistan's Election Commission, said the two parties "emerged as the main winners." He said they also won 19 out of 28 provincial seats that were up for grabs. Voting passed off mostly peacefully, except for a few minor incidents of violence, Dilshad said. He said turnout was low but did not have exact figures. The by-elections follow national elections in February that installed a new civilian government opposed to former army strongman President Pervez Musharraf. Most of the seats were vacant because the original victor won in more than one constituency and had to give up a seat. The results do not affect the balance of power in the 342-member National Assembly, where the People's Party controls 125 seats and Sharif's party holds 95 seats. The only significant upset was for the People's Party. A brother of Foreign Minister Shah Mahmood Qureshi lost to an independent candidate for a provincial assembly seat in Punjab. Sharif's party consolidated its control in Punjab, Pakistan's biggest province, securing 10 more seats there. The People's Party of slain ex-premier Benazir Bhutto won four seats in Punjab, all three provincial seats contested in southern Sindh province, two in militancy-wracked North West Frontier Province and one in Baluchistan. The other eight provincial seats were split between independent candidates and the Awami National Party, a minor partner in the coalition. The two main partners in the federal government have an uneasy alliance. Sharif's party has pulled out of the Cabinet over a dispute on how to reinstate senior judges purged by Musharraf last year.