Mahi, son of former president and founding secretary general of the BNP AQM Badruddoza Chowdhury, and Babar attacked each other personally, but the issue of the much-talked about 'third force' as proposed by Badruddoza also figured in their squabble.

According to the passengers of the flight, the two got into an argument over downgrading of cabin status of Badruddoza's daughter Mona Chowdhury and her husband Rafiqul Alam from Business Class to Economy Class.

Sources said Mahi became agitated when he came to know that their ticket was downgraded to upgrade the relatives of Babar.

At one point, the state minister raised the issue of the so-called 'third force' and asked, "Why are you not resigning?"

Mahi replied: "There has been no such event that calls for my resignation."

As their voices peaked, their relatives pacified them.

When contacted, a high Biman official told The Daily Star that he was not aware of the incident. "But the Biman authorities can upgrade or downgrade tickets if necessary."

Mahi told The Daily Star that he would not comment on the matter. He will hold a press conference today to clarify his political position.