The Democratic People's Republic of Korea (DPRK) vowed on Saturday that it would enhance its nuclear deterrence to counter the U.S.-South Korean joint war exercises, which will start on Sunday.

A statement issued by a spokesman for the DPRK's National Defense Commission said that the DPRK would legitimately counter "the largest-ever nuclear war exercises" with their powerful nuclear deterrence, the official KCNA news agency reported.

He warned that the United States and South Korea would "realize what high price they will have to pay for their reckless military provocation."

If Washington and its allies continued their nuclear threats, the DPRK will further bolster up its nuclear deterrence, and the denuclearization of the Korean Peninsula will become more difficult, he added.

The United States and South Korea have agreed to stage a series of joint naval and air drills starting next week. The first joint exercise involving the U.S. aircraft carrier USS George Washington will take place on July 25 in waters off the east coast of the Korean Peninsula, and the two allies plan to stage more drills down the road in both the Yellow Sea and the East Sea.

The DPRK spokesman blasted the war exercises as "nothing but outright provocations aimed to stifle the DPRK by force of arms," and called them "an unpardonable second military provocation to the DPRK" after Seoul's publication of results of investigation into the "Cheonan" warship sinking case.

He said it is a "natural option of the army and people of the DPRK" to take corresponding all-out retaliatory measures" as the United States and South Korea violated their promises that they would not attack or invade the DPRK with either nuclear or conventional weapons.

The U.S.-South Korean war games come amid rising tensions between the DPRK and South Korea over the sinking of a South Korean warship in late March.

The 1,200-ton "Cheonan" with 104 crew members onboard sank on March 26 near the maritime border with the DPRK after an unexplained explosion. Only 58 sailors were rescued alive shortly after the sinking.

On May 20, South Korea released the results of the investigation by a multi-national team, saying that the "Cheonan" was sunken by the torpedo of the DPRK.

The DPRK National Defense Commission issued a statement immediately to reject the claim of South Korea and asked to send an inspection group to the south to verify material evidence. However, the request was turned down by South Korea.