President-elect Joe Biden chose more senior aides to lead his administration's efforts to defeat the coronavirus and rebuild the US economy, and his office confirmed on Sunday he would begin receiving classified briefings that are an essential step toward taking control of national security.

As the Democratic former vice-president prepared for his move to the White House, Republican President Donald Trump pledged to maintain his legal fight to overturn the result of the Nov 3 vote even while indicating in comments to Fox News that he was growing resigned to leaving office on Jan 20...