A Russian-American lobbyist on Friday said he attended a June 2016 meeting with US President Donald Trump’s son that was allegedly held as part of Kremlin’s effort to help Trump’s election campaign, BBC reported.

Rinat Akhmetshin, who claims to be an ex-Soviet counter-intelligence officer, said he attended the meeting where Donald Trump Jr was promised Kremlin-linked material about Hillary Clinton. “I never thought this would be such a big deal, to be honest,” Akhmetshin was quoted as saying by AP.

The Congress has asked Donald Trump Jr to publicly testify about the meeting.

Trump’s son, his son-in-law Jared Kushner and campaign chairperson Paul Manafort had met Russian lawyer Natalia Veselnitskaya, who was accompanied by Akhmetshin, on 9 June 2016, according to the emails revealed by Donald Trump Jr. The meeting was arranged under the premise that Veselnitskaya would share important information about Clinton, added the report.