U.S. President Donald Trump on Thursday described the crisis between Rwanda and the Democratic Republic of Congo as a "very serious problem."

During a news conference about an air collision in Washington, Trump was asked if he had a plan to bring peace in DRC, where a conflict in the east of the country - that Washington, the U.N. and others say involves Rwanda - has escalated.

"You're asking me a question about Rwanda, and it is a very serious problem, I agree, but I don't think it's appropriate right now to talk about it. But it is a very serious problem," he told reporters.