A National Security Guard team on Monday arrived in Ludhiana to probe the blast at a multiplex, which left six persons dead.

"Teams of NSG and forensic experts have reached the site and are taking into possession the material that was found inside the Shringhar cinema after the blast," ADGP (Law and Order) Chandershekhar told PTI.

He said the services of army experts dealing with explosives were also being taken for a 'proper analysis.'

Six persons were killed and 30 others injured in the blast in the multiplex located in a busy shopping area of this industrial town on Sunday night. The ADGP did not rule out the hands of extremists or terrorists behind the blast.

"One thing is sure that the RDX was not used in huge quantity... yes there is possibility of use of RDX in small quantity," he said.

Meanwhile, security has been beefed up in Jalandhar and extra police force deployed in sensitive areas of the city.

"Security at sensitive areas including railway station, bus stands and cinema halls has been beefed up and special barriers erected to check every vehicle to avoid any untoward incident during the ongoing festival season," S K Kalia, Superintendent of Police, said.

State Minister Manoranjan Kalia, who visited the incident site, said, "People of Punjab have already faced dark period of terrorism and they know how to give such elements a befitting reply."

He also ruled out the possibility of revival of terrorism in the state.