WASHINGTON (AP) — President Donald Trump's main doctor says in a health update that the medical team treating the president is "cautiously optimistic," but also notes that the president is "not yet out of the woods."

The latest assessment came Saturday night from Navy Commander Dr. Sean Conley. He reported that Trump had been up and around at his medical suite during the day and had been conducting business.

Medical experts say the disease caused by the virus, COVID-19, can become more dangerous as the body responds to the infection over time.

Trump is expected to remain at Walter Reed National Military Medical Center for several more days. In a video Saturday from his hospital quarters, Trump says he is feeling better and hopes to "be back soon."