Pentagon slams `unhelpful` North Korea nuclear rhetoric

District of Columbia: North Korean threats of pre-emptive nuclear strikes against South Korea and the United States are "unhelpful" and serve only to aggravate tensions, the Pentagon said Monday.

The US military has downplayed the risk from North Korea`s nuclear arsenal and was going ahead with a joint annual exercise with Seoul involving 300,000 South Korean and around 17,000 US troops.

North Korea had earlier Monday warned of pre-emptive and "indiscriminate" nuclear strikes against South Korea and the United States as the two allies started the military exercises.

"That is rhetoric that is unhelpful," Pentagon spokesman Captain Jeff Davis said.

"We continue to ask them to refrain from provocative actions and statements that only serve to aggravate tensions."

Davis added that Washington and Seoul continue to move toward deployment of a sophisticated US missile defense system to South Korea.

He said the two countries last week signed "terms of reference" for the Terminal High Altitude Area Defense System (THAAD) deployment.