LONDON — The chairman of the British Parliament's media committee said Sunday that a millionaire backer of the successful campaign to leave the European Union has questions to answer about his contacts with Russian officials.

Lawmaker Damian Collins said his committee plans to question Arron Banks, co-founder of the Leave.EU campaign group, later this week. The announcement came after the Sunday Times newspaper reported that Banks' contact with Russian officials was more extensive than previously acknowledged.

"He said he only met the Russian ambassador on one occasion; we now know it was more than that. There were trips to Moscow, you know, supposedly lucrative business deals offered. Did those business deals go through?" Collins said in an interview with the BBC. "Was that money made used in political campaigning? I think these are all important questions, and I think people will want to know the answer."

Leave.EU was backed by Nigel Farage, the former chairman of the U.K. Independence Party who pressured the British government to hold a referendum on EU membership. The group operated separately from the official Vote Leave campaign.

The Times said Banks held three meetings with Russian Ambassador Alexander Yakovenko. One of the meetings was a November 2016 lunch three days after Banks visited Donald Trump, then president-elect, along with Farage and another prominent Brexit campaigner, Andy Wigmore.

The newspaper said its journalists saw emails that showed Banks discussed a potential business deal involving six Russian gold mines.

"I had two boozy lunches with the Russian ambassador and another cup of tea with him. Bite me," The Sunday Times quoted Banks as saying. "It's a convenient political witch-hunt, both over Brexit and Trump."

Banks also told the paper nothing came of the gold mine discussions.

"We didn't profit from any business deals because I never pursued anything," he said.