Washington (CNN) North Korea is "building new missiles, new capabilities, new weapons as fast as anybody on the planet," and learning from its mistakes as it makes advances in its missile programs, the No. 2 general at the Pentagon said Friday.

Air Force Gen. John Hyten, the vice-chairman of the Joint Chiefs of Staff, made the comments as talks between Washington and Pyongyang over North Korea's nuclear program have stalled and Kim Jong Un has signaled he may be ready to test more missiles that could be capable of hitting the United States.

"If you want to go fast in the missile business you need to test fast, fly fast and learn fast. Look at Space X in this country. There were some pretty spectacular failures. Did they stop? No," Hyten said while speaking at the Center for Strategic & International Studies in Washington.

"That is what North Korea has been doing and North Korea has been building new missiles, new capabilities, new weapons as fast as anybody on the planet with the 115th most powerful economy in the world. Speed itself is efficiency," he added.

The Trump administration has reached out to North Korea to resume diplomatic negotiations after the two countries broke off talks in October, White House national security adviser Robert O'Brien told Axios over the weekend.

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