Four persons -- a BJP sympathiser and three members of a minority community -- were injured in separate incidents at Tanur early on Wednesday, an autorickshaw driver was waylaid and attacked at Tirur around noon, police said.

Activists of the National Democratic Front allegedly killed RSS activist Ravi on January 20 in Tirur.

After the killing, the RSS observed a dawn-to-dusk shutdown in the district on Sunday. Inspector General of Police (North) M N Krishnamurthy said the Tanur incidents had nothing to do with the happenings at Tirur.

"The situation is very much under control and a strict vigil is being maintained throughout the district," he said.

In all, nine people had been injured in attacks in the district with RSS and NDF blaming each other for the clashes.

Meanwhile, posters, purportedly put up by the NDF in protest against the visit of Gujarat Chief Minister Narendra Modi to Kerala, were found at some places in the district but the police did not say if that had anything to do with the ongoing attacks.

In an attempt to instill confidence among the people, the district administration decided to extend the ban on two-wheelers in Tirur taluk till Thursday evening.

Ten people had been taken into custody in connection with the incidents, while raids were conducted at various places in search of those responsible for the attacks, police said.