Prime Minister Rajiv Gandhi and his ruling Congress (I) Party will run for election in national balloting by nearly 400 million Indian voters on Dec. 24.

The Election Commission announced today that the voting will continue on Dec. 27 in states where security considerations make it difficult to complete the process in one day. The election will decide 515 of the 542 seats in the Lok Sabha (People's House), which is the governing chamber of Parliament.

Because of civil unrest, elections will not be held on schedule in Punjab or the far northeastern state of Assam. Voters in Sikkim and the Union Territory of Pondicherry, which are under central government rule, also will not go to the polls.

Punjab and Assam will have elections at a future, unspecified date, and Sikkim and Pondicherry when central "president's rule" is lifted, chief election commissioner R.K. Trivedi said at a press conference.

He said that simultaneous state elections would be held in Manipur and the Union Territories of Arunachal Pradesh and Goa, and that the south Indian state of Tamil Nadu may hold a simultaneous state election if it notifies the commission within the next two days.

The elections will take place about three weeks before the mandatory expiration of the current Parliament on Jan. 20, although Gandhi could have used a constitutional loophole to postpone the balloting until June.

Gandhi is expected to run for the parliamentary seat from Amethi, in Uttar Pradesh state, which before him was held by his late brother, Sanjay, who died in a stunt plane crash in 1980.