New Delhi, Jan 17 (IANS): Supporters of Baba Ramdev and Congress workers clashed outside the Congress party headquarters here Monday after the yoga guru's men blackened a poster of party chief Sonia Gandhi.

Police said two Ramdev supporters, identified as Narendra and Tribhuwan, both from Delhi, have been arrested.

According to eyewitness, a group of 20-25 Ramdev supporters shouted slogans and blackened Gandhi's poster on a board outside the Congress' 24, Akbar Road office around 5 p.m.

Congress workers then rushed out and an altercation between the two group followed in full view of the TV cameras and media persons.

A Congress leader told IANS that the protestors were planning to disrupt the party press briefing scheduled at 5 p.m.

Baba Ramdev issued a statement, condeming the action of his supporters.

"Such undemocratic and uncivilized methods of protest should not be encouraged. Such acts have no place in our rich culture and philosophy," he said.

Activist Anna Hazare too released a statement in Ralegan Siddhi, criticising the protest.

The incident comes days after the yoga guru was himself the victim of a similar attack, when a man poured black ink on him during a press briefing.

The yoga guru's supporters have alleged that the attack was masterminded by the Congress.

Meanwhile, the Congress blamed the Bharatiya Janata Party (BJP) and allied organisations for the incident.

"Prima facie facts available to us make it very clear that this is the handiwork of our political opponents. Political opponents, including the BJP but other so-called peripheral and marginal elements, are constantly trying to promote the BJP agenda. It is extremely unfortunate," party spokesperson Abhishek Manu Singhvi said.

Terming the incident as tragic, he said it insults and demeans Indian democracy.

He said far bigger forces had tried "in much more obstructive manner to do such things" and the Congress party had always "emerged stronger and more successful".

Answering queries about Congress workers beating protesters, Singhvi said he was not aware of all the facts but no one can justify violence.

However, he added that action of protesters was "provocative".