United States Health and Human Services Secretary Alex Azar has resigned after the violent riots at the Capitol more than a week ago, according to U.S. media.

Azar said in a letter to President Donald Trump that his resignation would become effective on January 20, when U.S. President-elect Joe Biden is sworn in. He would have left office once Biden takes the presidential oath. 

The letter, obtained by U.S. media, is dated January 12.

In the resignation letter, Azar also condemned the violence in the storming of the U.S. Capitol on January 6 that has left five people dead. 

"The attacks on the Capitol were an assault on our Democracy and the tradition of peaceful transitions of power that the United States of America first brought to the world," he said.