Yoga guru Baba Ramdev and activist Anna Hazare's day-long fast against corruption and black money here on Sunday was marred by an open rift with Team Anna member Arvind Kejriwal walking out after he was chided by Ramdev for naming MPs.

Addressing a crowd of thousands, mainly Ramdev followers, who gathered at the Jantar Mantar on a hot and sultry Sunday, the yoga guru reiterated his demand that the government bring back all black money stashed away in foreign banks.

Ramdev launched a direct attack on Prime Minister Manmohan Singh asking him to ensure honesty in his cabinet.

Taking a dig at the joint fast by the two, Samajwadi Party leader Shahid Siddiqui said their alliance would 'not yeild any result', while the Congress said the repeated attacks on 'democratic institutions' were not 'good' for the nation.

Taking on the Prime Minister, Ramdev said: "The Prime Minister said that 'I am honest', but the country does not see you as an individual.

"The nation respects you for being an honest individual, but you should also be honest politically. The country sees you as the person holding the highest constitutional post. Your personal honesty is not enough. Keep your cabinet honest," he said.

Kejriwal took the attack a notch further, saying that Parliament would never pass the Lokpal bill as long as 'MPs like Lalu Prasad, A. Raja and Suresh Kalmadi were present'.

Ramdev was quick in snubbing Kejriwal for naming MPs, though he had started the day by attacking the Prime Minister.

"Today, we thought that we will not take any body's name. But Arvind took the names," Ramdev said after Kejriwal had finished his speech, adding that it would attract 'unnecessary controversy'.

Kejriwal left the venue soon after the open snub. He, however, tweeted later that he left because he was not well.

SP leader Shahid Siddiqui said Anna Hazare and Ramdev were together because they 'need each other's support' and this alliance 'will not lead to any result'.

"Ramdev has no reputation, though he has money and even an entertainment factor. Anna Hazare has a good reputation, but his group has left him alone. So both are supporting each other because they need each other, but this will not lead to any result," Siddiqui said.

The Congress too criticised the sit-in by the Hazare and Ramdev, and the latter's attacks against the Prime Minister, saying it was "not in the favour of the nation."

Union Minister of State for Agriculture Harish Rawat said the activists, in the name of fighting corruption, were destroying democratic institutions.

"In the name of fighting corruption they want to destroy all institutions. It will not be accepted," Rawat said.

In the morning, before beginning the fast, Ramdev and Hazare visited Rajghat, the memorial of Mahatma Gandhi. Both sat there in meditation for a while, and then went to nearby Shahid Park.

The two then along with supporters reached Jantar Mantar around 10 a.m.

Ramdev, accompanied by his close aide Acharya Balkrishna, also went to Tikri Kalan village in Delhi's outskirts and paid tributes to Netaji Subhash Chandra Bose at a memorial there.

At Jantar Mantar, pictures of Rajbala, a 51-year-old woman who died after being injured during the alleged police action on Ramdev supporters at the Ramlila ground agitation last year, were on display.

Elaborate arrangements were in place for the sit-in at Jantar Mantar. Besides Delhi Police personnel, 20 companies of paramilitary forces have been deployed and CCTV cameras installed to maintain security.

The fast has been called to mark one year of Ramdev's last agitation at Ramlila ground, from where he was arrested in the middle of the night between June 3 and 4 last year.