"Is this promise another cruel joke like the Congress's promise of 'garibi hatao'?" Mayawati asked.
Congress chief Rahul Gandhi's promise to provide the poor with a Basic Minimum Income has sharp attack from an unexpected quarter. Mayawati, one of the key opposition leaders ripped into the Mr Gandhi, comparing his promise with the potent "Garibi Hatao" slogan of his grandmother and former Prime Minister Indira Gandhi.
A couple of more recent promises, made by the BJP, were also cited by the Dalit leader, who questioned if the Congress pitch was a "cruel joke".
Mr Gandhi's big election promise, which he called a "historic decision", has drawn jibes from the BJP, which called it a political gimmick.
There have also been questions on how the Congress plans to fund such a programme without raising the country's fiscal deficits. Two years ago, a similar plan in the Economic Survey was dropped, with the government saying it was not "politically feasible" at the time.
A statement from Mayawati today read: "Is this promise another cruel joke like the Congress's promise of 'garibi hatao' or that of the present BJP government of depositing Rs. 15 to 20 lakh in the account of all the poor or 'achchey din' which have only proved to be hollow promises?"
The comments are seen as indications of an expanding rift between the Congress and the key Uttar Pradesh party that flared up since seat sharing talks fell through last year ahead of assembly elections in Madhya Pradesh, Chhattisgarh and Rajasthan.
Mayawati and Akhilesh Yadav have kept the Congress out of the alliance in Uttar Pradesh. Over the following weeks, Rahul Gandhi has responded with two moves - promising to contest all 80 seats in the state and inducting sister Priyanka Gandhi Vadra as the party general secretary from the eastern part of the state - that signals the party's intention to be a serious player in the state.
Mayawati has not commented on either move. But today, she said the record of both BJP and Congress is not good when it comes to election promises. Even if such promises have been implemented, they have proved to be eyewash, said the leader, who has much of her support base among the Scheduled Castes - one of the poorest sections in the country.
The Garibi Hatao slogan of Indira Gandhi, coined ahead of the 1971 election had led to a Congress victory. But in later days, the Congress came under opposition attack for failing to deliver on the promise.
The BJP is also under attack for the two promises made ahead of the 2014 assembly elections by Prime Minister Narendra Modi.