Seoul, South Korea ? North Korea threatened on Monday to build nuclear weapons as a deterrent to what it calls a “hostile” U.S. policy — the communist government’s first public declaration of its nuclear ambitions.

The statement marked a sharpening of the North’s tone in its standoff with Washington.

U.S. officials say the North Koreans told them privately that the country already has nuclear bombs and plans to build more — but until now Pyongyang had not openly stated its intention to develop an arsenal.

“If the U.S. keeps threatening the DPRK with nukes instead of abandoning its hostile policy toward Pyongyang, the DPRK will have no option but to build up a nuclear deterrent force,” North Korea’s official news agency said, using the acronym for the nation’s official name, the Democratic People’s Republic of Korea.

Also for the first time, North Korea linked its nuclear efforts to rebuilding its moribund economy.

The North’s “intention to build up a nuclear deterrent force is not aimed to threaten and blackmail others but reduce conventional weapons under a long-term plan and channel manpower resources and funds into economic construction and the betterment of people’s living,” the North’s official news agency said.

During talks in April in Beijing, North Korea told U.S. diplomats it was willing to give up its nuclear programs in return for security guarantees and economic aid, which it needs to fight the severe privation and food shortages its 22 million people suffer.

Despite its economic plight, North Korea keeps a 1.1 million-strong military, the world’s fifth-largest. Its “army-first” policy calls on its hunger-stricken people to bear economic hardships in order to build a strong military. The North’s news media churn out daily propaganda filled with anti-American hate.

In 2001, North Korea for the first time admitted that the size of its conventional forces “hampers” its economy and offered to reduce them if the United States withdrew its 37,000 troops from South Korea.

President Bush, Japanese Prime Minister Junichiro Koizumi and South Korean President Roh Moo-hyun have had separate summits in recent weeks and agreed to seek a peaceful resolution to the crisis over North Korea’s nuclear programs.

But all three leaders have warned of tougher measures if Pyongyang escalates tensions.