New Delhi (PTI): BSP chief Mayawati on Tuesday asked Prime Minister Manmohan Singh to immediately resign from the post after BJP alleged that Samajwadi Party tried to bribe three of their MPs for abstaining from voting during the trust vote.

"Prime Minister Manmohan Singh should resign on moral grounds. This is a black day in the history of democracy," Mayawati told reporters here. Condemning the incident, she said the method adopted by the Congress to save its government was a "setback for democracy". "This would be written in black letters in history," she said.

Senior party leader Satish Mishra sought the intervention of President, saying that the first citizen should immediately dismiss the government. He said Prime Minister Manmohan Singh was claiming that the talks of bribing MPs were false and people who want to prove it should show the proof.

"Now, we have the proof," he said. Mishra alleged that the Samajwadi Party distributed Rs 500 crores last night to mobilise support for the government.