WASHINGTON, May 11 (Xinhua) -- The nuclear program of the Democratic People's Republic of Korea (DPRK) posed a "potentially existential threat" to the United States, U.S. National Intelligence Director Dan Coats said on Thursday.

"It's clear that we have assessed this as a very significant, potentially existential threat to the United States that has to be addressed," said Coats at a U.S. Senate hearing on world threats.

Calling the DPRK "an increasingly grave national security threat" to the United States, Coats said the DPRK had taken "initial steps" toward fielding a mobile intercontinental ballistic missile.

However, Coats refused to reveal the U.S. intelligence community's estimation about when the DPRK would have an intercontinental ballistic missile capable of taking a nuclear warhead.

Tension has remained high on the Korean Peninsula over the past months between the United States and the DPRK over the U.S. threat to stage military attacks against Pyongyang in response to its nuclear and missile programs.

The United States and South Korea also held their largest ever joint military exercises in the past two months. At the end of April, the USS Carl Vinson nuclear aircraft carrier task group arrived in the waters off the Korean Peninsula for a separate joint naval exercise with South Korea.

However, a joint statement by U.S. Secretary of State Rex Tillerson, Secretary of Defense James Mattis and Coats said last month that U.S. President Donald Trump aims to use economic sanctions and diplomatic measures to pressure the DPRK to dismantle its nuclear and missile programs.

The statement also said that the United States remained "open to negotiations" toward peaceful denuclearization of the Korean Peninsula while staying "prepared to defend ourselves and our allies."

The DPRK said early this month that the current crisis on the Korean Peninsula is the most dangerous in half a century since the 1950-1953 Korean War.

"If the DPRK had not had access to the powerful nuclear force and had not gotten itself ready to counter the U.S. and its vassal forces' provocation with merciless military counteraction, the U.S. would have committed without hesitation the same aggression act in Korea as what it committed against other countries," the official Korean Central News Agency quoted a foreign ministry spokesman as saying on May 1.