The United States urged North Korea on Monday to halt provocative rhetoric and threats after the communist nation threatened to launch an "all-out offensive" against South Korea and the U.S. as the allies kicked off annual military exercises.

The North's powerful National Defense Commission said earlier Monday the country will take "military counteraction for preemptive attack so that they may deal merciless deadly blows at the enemies" as the South and the U.S. began their annual Key Resolve and Foal Eagle exercises.

It also warned that major South Korean targets are within the North's firing range, and its nuclear strike capability can reach U.S. military bases in the Asia-Pacific region as well as the U.S. mainland.

"We do take those threats seriously, and again call on Pyongyang to cease with the provocative rhetoric, cease with the threats and, quite frankly, more critically, cease the provocative behavior," State Department spokesman John Kirby said at a regular briefing. 

North Korean leader "Kim Jong-Un has a choice he can make, which he clearly seems unwilling to make, which is to ratchet down the tension on the peninsula, to focus his resources and energy on the people of North Korea and on peace and security there in the region, rather than ... trying to up the ante with these kinds of comments," he said.

The spokesman stressed that the military drills are purely defensive.

"There's simply no reason for anybody to be angry or disconcerted about this exercise. They have been going on, as I said, for roughly 40 years, and they are designed to do what all military exercises are designed to do, to sharpen and improve coordination and capabilities, and that's what they're gonna do," he said.

The Defense Department issued a similar warning, saying such rhetoric is "unhelpful."

"We continue to ask them to refrain from provocative actions and statements that only serve to aggravate tensions," Pentagon spokesman Capt. Jeff Davis told reporters. 

State Department deputy spokesman Mark Toner said at a Foreign Press Center briefing that the goal of new U.N. sanctions adopted last week was to "apply increasing pressure on the elite within the DPRK, or North Korea, in order to encourage them to come back to denuclearization talks."

"We're going to apply that pressure. As we talked about when we passed this UN Security Council resolution, these are hard-hitting sanctions, but what really counts is the implementation of those sanctions," Toner said. 

He stressed that what brought Iran to the nuclear negotiating table was not just the sanctions on paper but their implementation.

"We want to try to apply that same rigid standard to North Korea, again, with the aspiration of trying to get them back to talk about denuclearization," he said. (Yonhap)