Even as Union Minister of State for Home I D Swami visited the violence-hit Marad village in northern Kerala's coastal belt on Monday, the police said Friday night's massacre was pre-planned and executed most probably with the help of extremist forces from outside the state.

Nine people were killed and several injured when a group of around 50 people armed with swords, knives and country-made bombs attacked Marad, a tiny fishing village.

Swami, who went around the village, later held a meeting with Kerala Chief Minister A K Antony and senior administrative officials.

The official version is that those behind the Marad killings could be related to those killed in the same village last year in a similar attack.

The wedge between the Hindus and Muslims runs deep in this coastal village. Militant Muslim organisations and the Rashtriya Swayamsevak Sangh have only added to the tensions by their provocative posturings.

A senior police officer said there is enough evidence to suggest that a few Muslim extremist groups may have been involved in Friday's massacre.

"The killings were pre-planned and executed in less than 15 minutes. We think there were trained extremists who accomplished the massacre with ease and got away," he said.

Recovery of powerful bombs made of gelatin sticks have strengthened the suspicions about the involvement of organised extremist elements.

Local RSS and Bharatiya Janata Party leaders, however, blame homegrown Muslim extremist groups and Pakistan's Inter Services Intelligence for the massacre.

RSS Kerala state secretary, A R Mohanan, said there were several warnings in the past about Kerala's vulnerability to fundamentalist forces that are aided by the ISI.

According to Mohanan, just last month Major General Anoop Singh Jamwal, General Officer Commanding, Southern Region, in his address at a top-level civil-military liaison conference in Thiruvananthapuram had warned that ISI was trying to get a foothold in the southern states.

"The killings in Marad is a clear instance of the Kerala government's failure to nip the Muslim fundamentalism-ISI threat in the bud," Mohanan told rediff.com.

Meanwhile, Chief Minister Antony said his government has initiated steps to establish fast-track courts to try cases related to the Marad killings.

"The guilty will be punished. My government is committed to ensure that those who plotted the horrific killings in Marad do not go scot-free," Antony said.