She filed papers on Wednesday in the Bellary constituency of the southern state of Karnataka, after flying in by helicopter from Hyderabad.

Members of her party have indicated that Mrs Gandhi may also seek election from Amethi in Uttar Pradesh, formerly represented by her late husband, Rajiv.

In India, candidates are allowed to run in up to 10 districts.

First attempt

David Chazan in Delhi says Congress has a lot of catching up to do

It is Mrs Gandhi's first attempt to enter parliament, and she would be expected to become the country's leader if Congress wins the election.

Critics say her Italian birth should bar her from doing so.

The issue of Mrs Gandhi's nationality is likely to figure prominently in the elections.

Sections within the governing BJP are said to feel there will be a benefit to the party in highlighting the issue.

Others, including Prime Minister Atal Behari Vajpayee, would prefer the party to distance itself from any approach that is negative.

But some of his party's more radical members, including the hawkish home minister, LK Advani, recall that a similar attack on Rajiv Gandhi over an arms scandal delivered rich dividends to an opposition coalition in 1989.

The power of a name

The Congress Party is likely to bank heavily on Mrs Gandhi's ability to draw votes as the natural inheritor of the Nehru-Gandhi dynasty.

Her decision to campaign for the party during the last elections energised party workers and helped reverse the party's declining electoral fortunes.

But the BBC Correspondent in Delhi, David Chazan, says her illustrious name and her image as a grieving widow are of little help this time.