California Rep. Maxine Waters accused President Trump of "bluffing" when he vowed "fire and fury" against North Korea if the country didn't stop threatening the U.S. with nuclear weapons.

"This is something we should be very concerned about, but this is not the time to go bluffing and threatening. This is the time for diplomacy," Waters told TMZ.

She called on Secretary of State Rex Tillerson to staff up his department so that the U.S. can "engage" with North Korea.

"The United States State Department must be stacked up to deal in diplomacy. We cannot afford to be in a war. I want us to be very careful, very alert to what is happening, and to avoid war," she said.

Waters also called on the U.S. to possibly concede on some issues if it means avoiding war.

"There are some things they want from us. We have to find out whether or not we can work with them on the things they're asking for," she said.

Trump on Tuesday warned North Korea it would face dire consequences if it continued to advance its nuclear weapons program.

North Korea responded by threatening Guam, which is home to a major U.S. military base.