Kolkata, Trinamool Congress' Lok Sabha MP Abhishek Banerjee on Sunday took a dig at BJP leaders for "not being able to sing the national anthem properly" at a rally in Kolkata's adjoining Howrah Dumurjala stadium.

"Those preaching patriotism and nationalism can't even sing our national anthem correctly. This is the party which claims to uphold India's honour and pride. Shameful," Chief Minister Mamata Banerjee's nephew said, sharing a video clip on his Twitter handle.

Calling this "anti-national" act, the leader of West Bengal's ruling party also demanded an "apology" from Prime Minister Narendra Modi, Union Home Minister Amit Shah and the BJP.

"Will Modi, Shah and the BJP apologise for this anti-national act?" he asked.

Former West Bengal Forest Minister Rajib Banerjee, Bally legislator Baishali Dalmiya, Uttarpara MLA Prabir Ghoshal, ex-Howrah Mayor Rathin Chakraborti and Bengali actor Rudranil Ghosh, who had joined BJP on Saturday, were present on the stage with Union Minister Smriti Irani, BJP state President Dilip Ghosh, Suvendu Adhikari, party's national Vice-President Mukul Roy, General Secretary Kailash Vijayvargiya when the national anthem was sung.