The U.S. called off nascent talks with North Korea aimed at formally ending the Korean War when it became clear that the reclusive nation wasn’t interested in stopping its nuclear program by conducting a ballistic missile test.

The talks, which Pyongyang requested according to the U.S., ended after North Korea rebuffed a U.S. demand that denuclearization be a condition for the negotiations, Obama administration officials said. The U.S. and North Korea reached an agreement in 2005 with other nations including Japan and South Korea that set the groundwork for future talks premised on denuclearization.

“To be clear, it was the North Koreans who proposed discussing a peace treaty,” State Department spokesman John Kirby said Sunday in an e-mailed statement. “We carefully considered their proposal, and made clear that denuclearization had to be part of any such discussion. The North rejected our response. Our response to North Korea’s proposal was consistent with our longstanding focus on denuclearization.‎”

QuickTake North Korea's Nukes

The U.S. has leaned on China to play peacemaker with North Korea, its ally, since Washington and Pyongyang don’t have formal diplomatic relations. North Korea’s nuclear test and long-range rocket launch earlier this year led senior Chinese officials to advocate the signing of a peace treaty to replace the 1953 armistice that ended the Korean War, saying the Kim Jong Un regime would otherwise continue its arms development. North Korea has long made the same demand, calling the cease-fire a source of mistrust blocking progress in its nuclear standoff with the U.S.

"Though China is not the crux of the Korean Peninsula nuclear issue, as the host of the six-party Talks, it always actively discusses with other parties on feasible ways to solve the issue from an objective and just stance," Chinese Foreign Minister Wang Yi said last week. "To this end, China proposed the negotiation thinking to advance denuclearization on the Korean Peninsula in parallel with transition from armistice to peace."

Shining Star

North Korea successfully launched a “Kwangmyongsong,” or shining star, satellite into orbit this month. Pyongyang continues to develop a mobile intercontinental ballistic missile that “would likely be capable of reaching much of the continental United States,” the Pentagon said in a report to Congress on the secretive regime’s military capabilities.

The North Korea talks were reported earlier by the Wall Street Journal and CNBC. Major hostilities in the Korean War ended in 1953, but the conflict never officially ended.

Obama has recently warmed relations with adversaries. The U.S. spurred negotiations in recent months with Iran, with whom it also doesn’t have formal diplomatic ties, on the release of U.S. prisoners held by Tehran. In 2015, the president reopened diplomatic relations with Cuba.