By Tom Gibb BBC correspondent in Sao Paulo

A corruption scandal which has split the government has forced the only woman so far to stand in Brazil's presidential elections to quit her campaign.

Ms Sarney says she has been the victim of a "war operation"

Roseana Sarney was until recently also the favourite to win the presidential race.

She admitted that a police corruption investigation had undermined her chances of winning the elections due to be held in October but she blamed rivals in the government, accusing them of waging a war against her.

Ms Sarney - the daughter of a former president and herself a former state governor - belongs to a powerful political clan in northern Brazil.

But the police raided a company belonging to her and her husband as part of an investigation into the siphoning off of some $2bn from a development fund for the Amazon.

Unexplained cash

It is Brazil's biggest running corruption scandal and it has already claimed the heads of several other top politicians and split the government.

The police took away documents and more than $500,000 of unexplained cash which Ms Sarney now says was money donated illegally for her campaign.

The raid led to Ms Sarney's Liberal Front Party leaving the government alliance in protest.

She claimed she was a victim of foul play by a rival government candidate.

President Cardoso is trying to keep his government together

Announcing that she would no longer be running for president, she repeated these accusations, saying that there had been a war operation, including bugged telephones and police surveillance, to destroy her candidacy.

However, she has found little sympathy in the Brazilian press, which has been running daily stories about her possible involvement in the Amazon development scandal.

In the end Ms Sarney was apparently asked to stand down by members of her own party who saw her as more of a liability than an asset.

The clear winner from this situation is the man likely to become the government's official candidate, former Health Minister Jose Serra.