Pakistan's Election Commission is holding an emergency meeting Monday to decide how and when to proceed with parliamentary elections following the assassination of former Prime Minister Benazir Bhutto.

On Sunday, an official of the country's ruling party, Pakistan Muslim-Q said the vote originally set for January 8 could be delayed up to 12 weeks.

The Election Commission says many of its offices were set afire during riots that broke out after Ms. Bhutto's death. Lists of voters were destroyed, the commission says, and the disorders also affected other election preparations.

Ms. Bhutto's Pakistan People's Party has decided to take part in the elections, but a senior PPP official says any postponement of voting would be unacceptable.

The PPP's decisions Sunday prompted Pakistan's other main opposition party, led by former Prime Minister Nawaz Sharif', to drop its previous boycott plan and announce that it, too, will take part.

The Pakistan People's Party, founded by Ms. Bhutto's father, chose her son and husband to succeed her in the party leadership.

19-year-old Bilawal Bhutto Zardari and his father, Asif Ali Zardari, were chosen Sunday as PPP co-chairmen. The elder Zardari is expected to run the party while the teenager completes his university studies in Britain.

In Washington Sunday, the State Department said it is essential that Pakistan's Election Commission name a specific new date for voting at the same time it announces any delay in balloting beyond next week.

The deadly riots triggered by Ms. Bhutto's assassination on Thursday eased on Sunday -- the last of three days of national mourning. Some food markets and other businesses have reopened in Karachi and more are expected to do so shortly.

One report (AFP) quotes Pakistan's railway minister as saying that train service between Karachi and northern cities including Islamabad and Lahore will resume Monday evening.

Some information for this report was provided by AP and Reuters.