Kolkata, Mar 24: Authorities in West Bengal sealed the Indo-Bhutan border along the northern part of the state as the Himalayan kingdom went for its first Parliamentary elections today. "The entire Indo-Bhutan border has been sealed. The border stretches for about 200 km from Darjeeling to Jalpaiguri. The measure has been taken to prevent transborder movement," Inspector General of Police (Law and Order) Raj Kanojia said. Mr.Kanojia said security had also been beefed up at Jaigaon-Phuntsholing border in Jalpaiguri district. Bhutan experienced an explosion at the border town of Samdrup Jongkhar, close to the Assam border on March 15.