US President Joe Biden tells reporters that he has been briefed by Transportation Secretary Pete Buttigieg and that "aircrafts can still land safely, just not take off right now," as he leaves the White House on his way to Walter Reed Medical Center. "They don't know what the cause of it is, they expect in a couple of hours they'll have a good sense of what caused it and we'll respond at that time," he adds. The Federal Aviation Administration (FAA) said that normal operations were resuming gradually as airlines warned of lingering delays. AFP