This is reported in the federal register-a collection of documents of the American government.
The sanctions were imposed earlier by the administrations of Donald Trump and Barack Obama.
Biden decided that all these restrictions “should remain in effect” after March 6, 2021.
“The actions and policies outlined in these executive orders continue to pose an extraordinary and extraordinary threat to U.S. national security interests and foreign policy,” the President said in an explanatory note.
He stressed that because of this, “he is extending the state of emergency declared by decree 13,660 for one year.”