Special Counsel Robert Mueller departs after briefing members of the U.S. Senate on his investigation into potential collusion between Russia and the Trump campaign on Capitol Hill in Washington, U.S., June 21, 2017. REUTERS/Joshua Roberts

WASHINGTON (Reuters) - Special counsel Robert Mueller has impaneled a grand jury in Washington to investigate allegations of Russia’s interference in the 2016 elections, the Wall Street Journal said on Thursday, citing two unnamed people familiar with the matter.

The grand jury began its work in recent weeks and is a sign that Mueller’s inquiry into Russia’s efforts to influence the election and whether it colluded with President Donald Trump’s campaign is ramping up, the Journal said.