Venezuelan opposition leader Juan Guaido spoke with U.S. Secretary of State Antony Blinken on Tuesday, four people familiar with the matter said, the highest-level U.S. contact with Guaido since President Joe Biden took office on Jan. 20.

The State Department did not immediately respond to a request for comment.

Washington recognized Guaido as Venezuela's rightful leader in January 2019 after Guaido, the leader of the opposition-held National Assembly, invoked the constitution to assume an interim presidency, arguing President Nicolas Maduro's 2018 re-election was fraudulent.

Maduro, who has held onto power backed by the South American country's military and allies including Russia, China and Cuba, argues Guaido is a U.S. puppet seeking to oust him in a coup.

Guaido and Blinken discussed the provision of humanitarian aid to Venezuela, which is suffering a years-long economic crisis, as well as the country's supply of coronavirus vaccines, according to one of the people, who spoke on condition of anonymity.