North Korea is able to launch a "limited" missile attack and the United States stands ready to defend itself, South Korea and Japan should such an event occur, the chairman of the US Joint Chiefs of Staff has said.

Marine Corps Gen. Joe Dunford made the assessment at the Aspen Security Forum in Aspen, Colorado, Saturday, as he emphasized his immediate concern about North Korea's missile and nuclear programs.

"(North Korean leader) Kim Jong-un's regime is tied to program, and what I can tell the American people today is North Korea is capable of launching a limited missile attack," he said according to an article released by the Pentagon Sunday. "The United States military can defend against a limited North Korea attack on Seoul, Japan, and the United States."

Dunford's remarks appear to be consistent with those made by his deputy last week.

Air Force Gen. Paul Selva, vice chairman of the JCS, told a Senate hearing the North has developed missiles with the range to hit the US, but without any degree of accuracy.

He was speaking based on the North's July 4 test of an intercontinental ballistic missile, which experts say could reach Alaska and potentially other parts of the US.

"Many people have talked about military options (against North Korea) with words like 'unimaginable.' I would shift that slightly to 'horrific,'" Dunford said. "It would be a loss of life unlike any we have experienced in our lifetimes. Anyone who has been alive since World War II has never seen the loss of life that could occur if there is a conflict on the Korean peninsula."

But the chairman noted it is possible to consider military options in Korea.

"What is unimaginable to me is allowing a nuclear weapon to land in Denver, Colorado. My job will be to develop military options to make sure that doesn't happen," he said.

Dunford called for continued diplomatic and economic pressure on North Korea, saying it remains the best option to force the regime in Pyongyang to curb its nuclear program and eventually denuclearize. (Yonhap)