Updated at 10:30 p.m. ET
President Trump says his chief economic adviser, Larry Kudlow, has suffered a heart attack and is being hospitalized.
Minutes before he began a one-on-one meeting in Singapore with North Korea's Kim Jong Un, Trump tweeted, "Our Great Larry Kudlow, who has been working so hard on trade and the economy, has just suffered a heart attack. He is now in Walter Reed Medical Center."