New Delhi, (PTI) Six left parties today urged the government to punish those responsible for the demolition of the Babri Masjid in Ayodhya and said they would continue to put pressure on it till the guilty were booked.

Marking the 25h year of the demolition of the 16th- century mosque as a "Black Day", the parties, including the CPI(M) and the CPI, said they would hold mass movements across the country till action was taken against the guilty.

"We will put pressure on the government through mass movements till the people responsible for the demolition of the Babri Masjid are booked," CPI(M) general secretary Sitaram Yechury said at a protest march in Delhi.

Leaders of the CPI(M), CPI, RSP, AIFB, CPIML and SUCI said at the march they would strengthen their struggle against "communal polarisation" which they alleged was being encouraged by the RSS and the BJP.

"We, six Left parties, take a pledge today that we will not let the country get divided. It is also our warning to the government," Yechury said.

The parties had called for observing the anniversary as a "Black Day" to protest against the "wilful demolition" of the mosque.

The parties said the Congress, which then ruled at the Centre, and the then BJP government in Uttar Pradesh were both responsible for the demolition on December 6, 1992.

"The reality is that 25 years down the line, not a single person has been punished or sent to jail on the criminal act of destroying the Babri Masjid," CPI(M) politburo member Brinda Karat said.

Then UP chief minister Kalyan Singh had given "repeated assurances" to the Supreme Court that nothing would happen to the mosque, she pointed out.

"And yet today Kalyan Singh has been rewarded by being made a governor. It is not a question of an individual. It is the question of an attack by the RSS BJP on the very foundations of the republic of India and the principles of the Constitution," she said at the march.

Yechury said on December 6, which is also the death anniversary of Dalit icon B R Ambedkar, the Left pledged to "mount a campaign against the intensification of assaults on Dalits across the country and on the secular democratic values of our Constitution by the communal forces".

Thousands of activists on December 6, 1992, had brought down the mosque in Ayodhya, demanding that a Ram temple be built there instead.