There are no plans for a US government evacuation from Sudan at this time but Americans should treat the volatile situation in the African country with utmost seriousness, White House national security spokesperson John Kirby said on Monday. "We urge American citizens in Sudan to treat this situation with the utmost seriousness," Kirby said in a briefing with reporters. He cited a State Department security alert for Sudan on Sunday that said there were no plans for a US government-coordinated evacuation at this time because of the uncertain security situation in Khartoum and the closure of the airport. "We expect that will remain the case," Kirby added.