'Passengers of Gaya Passenger Train were also stopped by the Congress activists to alight on the Sreerampore station when the train halted there for while,' he said.

According to reports, a group of enraged Congress supporters vandalised the head post office in Siliguri town of Darjeeling district.

'We've received a report that the head post office in Siliguri was vandalised by some political activists today morning. Another group of people, who were supporting the shutdown, also damaged the wind screens of a government bus in the same town,' state Inspector General of Police (North Bengal) K.L. Tamta told IANS.

'At least four people have been arrested so far in connection with these two protests in Siliguri,' he said.

Shops, schools, factories, offices remained closed and vehicles also kept off the roads as the supporters of the strike waving party flags took to the streets.

'The number of public transport was noticeably low in and around Kolkata. We had issued a notice to all state government departments to keep their regular service on. But it was somehow affected due to the strike,' state Chief Secretary Ashok Mohan Chakraborty said.

Train services were paralysed while some airlines rescheduled or cancelled their flights.

Many long-distance and local trains were halted midway by protesters. A number of trains -- like Biswabharati Fast Passenger, Asansol-Haldia Express, Howrah-Purulia Express and Steel Express -- were stopped at different railway stations as Congress supporters squatted on tracks.

'Both Howrah-New Delhi and Sealdah-New Delhi Rajdhani Express trains were rescheduled following the strike,' Eastern Railway spokesperson Samir Goswami said.

Police said a long-distance bus was damaged by mobs at Baguihati near the airport here.

'Four people were detained when they were trying to shut the Metro Railway station gate at Kalighat,' Kolkata Police deputy commissioner (detective department) Jawed Shamim told IANS.

Attendance in IT and outsourcing firms here was also affected, officials said.