The United States, South Korea and Japan said Wednesday that North Korea must end its nuclear program if it wants better ties, after Pyongyang said it was willing to return to talks.

"We will judge the DPRK by its actions, not its words," the democratic allies said in a statement, referring to the North by its official name, the Democratic People's Republic of Korea.

Glyn Davies, the US special representative on North Korea policy, met his counterparts from Japan and South Korea amid a flurry of discussions on North Korea in the wake of a dramatic diplomatic crisis earlier this year.

"We agreed a path is open for the DPRK toward improved relations ... if the DPRK takes meaningful steps on denuclearization," the statement said.

The United States, South Korea and Japan said that they stood by a 2005 agreement -- made at six-way talks that include three allies as well as China and Russia -- to make verifiable efforts to end its nuclear program.

Since then, North Korea has tested three nuclear bombs, most recently in February. Its latest test was accompanied by rhetoric fiery even by North Korea's standards, including threatening nuclear war on the United States.

China said North Korea's veteran negotiator Kim Kye-Gwan had voiced an interest in returning to the six-way talks, which have been dormant since 2008, during talks on Wednesday in China.

In recent weeks North Korea has also agreed to talks with Seoul, which ultimately did not take place, and offered direct dialogue with the United States.

Davies said in a speech last week that North Korea's actions this year set the bar higher for the resumption of dialogue, and urged the communist state to address the nuclear issue as well as concerns such as human rights.

China is North Korea's main ally, but US President Barack Obama recently praised the rising Asian power for taking a harder line against Kim Jong-Un's regime.

The South Korean representative on North Korea policy, Cho Tae-Yong, will head to Beijing after leaving Washington.

UN Secretary-General Ban Ki-moon was also visiting China, where he spoke Wednesday with President Xi Jinping about the Korean peninsula and other issues.