Transcript for US Senate receives a rare classified briefing on North Korea and its nuclear threat

Now to the intensifying showdown with North Korea tonight and a rare meeting late today, all 100 senators invited to the white house. Traveling by bus for a briefing on North Korea with president trump's national security team. And with tensions rising American and south Korean troops taking part in a military exercise today. North Korea tonight, warning that the U.S. Playing with fire end quote. Here's ABC's Cecilia Vega. Reporter: Today, a field trip to the white house. One by one, nearly every senator on capitol hill loading up on buses. I must be in the right place! Heading to that classified briefing on North Korea and its nuclear threat. Inside the bus, Connecticut senator Chris Murphy tweeting, "On board the bus to the 100 days photo-op/north Korea briefing." That briefing came at the request of senate majority leader Mitch Mcconnell. The president offering up his top national security advisers for the task. And the white house for the meeting space. The senators just all arrived here at the white house. We can't see them, they're being kept pretty far away from us, this is what you can see. All the photographers trying to get that shot. Those cameras catching the president stopping by. An hour and 20 minutes later, the senators emerged. After what you heard in there today, how would you characterize the threat? They're making advancements. The military is obviously planning for a number of options, as well they should it's of course the hope of the administration and congress that military action doesn't prove necessary. Reporter: North Korea had a response to the briefing before it even began, saying in a statement, there is a saying that those who a fond of playing with fire are destined to perish in the flames. The same can be said of the U.S. In an effort to demonstrate its firepower, the hermit kingdom on Tuesday conducting massive artillery drills to mark the 85th anniversary of its military. A move China strongly opposes at a time when U.S. Needs beijing to be on its side when it comes to knot kree. Cecilia joins us live from the white house tonight. What more have you learned tonight about what they were told in that room. Reporter: David it was a classified meeting. Some senators felt like they didn't learn anything new. The white house suggests new sanctions against North Korea could be the next move.

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