New Delhi, March 20 (IANS) The Bharatiya Janata Party (BJP) Saturday sought an apology from Prime Minister Manmohan Singh for "taking Delhi to Pakistan and Kolkata to Bay of Bengal" in a railway advertisement goof-up.

"The prime minister should apologise to the nation. An important ministry has taken Delhi to Pakistan and Kolkata to Bay of Bengal. We are ashamed of it," BJP spokesman Ramnath Kovind told IANS.

The faux pas occurred in the advertisement in major newspapers publicising the scheduled flagging off of a luxury tourist train Maharajas' Express by Railway Minister Mamata Banerjee Saturday night.

The Congress, however, dismissed the demand.

"It is a childish demand. It has nothing to do with the prime minister," said Congress spokesman Shakeel Ahmed.

He said it was a "careless mistake" by a government department and "it is very unfortunate that the BJP was trying to politicise it".

The route of the train in the advertisement was shown by tracing a blurred outline of a map of India within a small box in the advertisement. The outline gave the wrong locations of the national capital and the eastern metropolis.

The Eastern Railway regretted the error but put the blame on the Kolkata-based advertising agency.