NEW DELHI: West Bengal Congress chief Adhir Ranjan Chowdhury on Friday said he has expressed his regret to Trinamool’s Rajya Sabha leader Derek O’Brien for calling him a “foreigner”.

“I conveyed my regrets to MR DEREK O’BRIEN for an word inadvertently uttered by me on him as FOREIGNER,” Chowdhury said in a post on X, formerly Twitter, on Friday.

The war of words escalated on Thursday with O’Brien calling Adhir Chowdhury’s relentless attack on West Bengal chief minister Mamata Banerjee as the main reason for Trinamool’s decision to go solo in the Lok Sabha polls.

Hours later when after Chowdhury was asked about O’Brien’s statement that he and BJP were speaking in the same language, Chowdhury brushed aside the question: saying: “He (O’Brien) is a foreigner, he knows a lot of things. Ask him…”

The Congress leadership is learnt to have nudged Chowdhury on the issue.

The attack on O’Brien came amid Banerjee pulling out of the alliance in Bengal citing a delay in seat talks. While the Congress leadership is trying to placate Banerjee by hailing her as the tallest leader in Bengal and an inseparable part of the alliance, Chowdhury’s barb is set to make the relationship more complicated.

Chowdhury, a fierce critic of Banerjee, has been known to oppose any alliance between the Congress and the TMC. The Trinamool has alleged that since the alliance was formed on June 23 last year, the Congress leader continued to attack Banerjee.

O’Brien also accused that “Chowdhury is the voice, but content is provided by the two people in Delhi”.