The United States must work for a formal peace treaty between North Korea and South Korea, 57 years after the armistice that left the neighbors technically at war, a US lawmaker urged Monday.

"Further isolating North Korea from South Korea and the international community does not serve the interest of any country truly dedicated to regional stability," said Democratic Representative Dennis Kucinich.

Kucinich called for Washington to use its "unique role" in the region to "work toward peace and facilitate a lasting peace settlement between North and South Korea" sixty years after the start of the 1950-1953 Korean war.

The lawmaker also scolded President Barack Obama's government over its response to the March sinking of a South Korean warship, claiming 46 lives.

South Korea, the United States and other nations -- citing the findings of a multinational investigation -- have accused the North of sending a submarine to torpedo the Cheonan warship near the tense Yellow Sea border.

Kucinich said the sinking and North Korea's subsequent announcement it was severing all relations with South Korea were "a symptom of a failed policy in the region."

And he cited bitter US debate over the country's swelling government deficit and ballooning national debt and said the United States spends more than one billion dollars per year to garrison forces in South Korea.

"At a time when millions of Americans are out of work and are struggling to pay their bills, one billion dollars per year is needlessly poured into further militarizing the Korean peninsula," said Kucinich.