Angry CPI-M activists stoned the BJP headquarters here in Kerala on Friday prompting a similar attack from the latter within hours.

The BJP-RSS and CPI-M animosity in the state took a turn for the worse as both parties resorted to violence.

Hours after the Left party's attack, BJP workers stoned the residence of Communist Party of India-Marxist's state Secretary Kodiyeri Balakrishnan's son.

According to visuals released by the state BJP headquarters, around 1.40 a.m. few persons arrived at the Bharatiya Janata Party's office.

They smashed the window panes of around six vehicles parked inside the compound, including one that belonged to the party's state chief Kummanem Rajasehekeran.

"This is a planned attack and it was unleashed by the CPI-M after coming to know that our state President was staying overnight at the office," party General Secretary M.T. Ramesh told the media.

BJP's lone legislator O. Rajagopal told the media that the visuals showed the role of local CPI-M councillor I.P. Binu in the attacks.

Around 3.40 a.m., unidentified persons stoned the residence of Bineesh Kodiyeri, Balakrishnan's son.

"I was on my way back from Kannur, when I got this news. I was in the train," the CPI-M Secretary said.

Balakrishnan said he generally stays in the party apartment but "at times I stay with my son and may be the BJP and RSS activists thought I was staying there last night and hence unleashed the attack". 

"Only if a probe is launched will one know whether 'they' had planned to attack that place, too," Balakrishnan said, adding: "We condemn this attack as we do not subscribe to any such attacks."

There has been sporadic clashes here between the two groups in the past two weeks.

The clashes had all begun when the student wings of these two political parties clashed in two colleges here earlier.

Later the youth wings of both parties flexed muscles against each other.

On Thursday there were skirmishes between the workers of these parties at a few places in the city and its suburbs.

The police decided to strengthen security around both party offices.