President Obama met last week in California with Chinese President Xi Jinping. Ben Rhodes, U.S. deputy national security adviser for strategic communications, told reporters both leaders held "a lengthy conversation" about North Korea.
A February decision by North Korea to conduct an underground nuclear test sparked concern about the security situation on the Korean Peninsula. Nuclear talks among the Koreas, China, Japan, Russia and the United States have been suspended since 2008.
Rhodes said last weekend both presidents agreed the North Korean issue was a key area for bilateral cooperation.
"They agreed that North Korea has to denuclearize [and] that neither country will accept North Korea as a nuclear-armed state," he told reporters.
Alan Romberg, a 27-year veteran at the U.S. State Department, said the Chinese stance represents a subtle shift in its relationship with North Korea.
He writes on John Hopkins University's North Korean forum 38 North the previous Chinese administration was expressly concerned about its stability in relation to issues on the Korean Peninsula.
"China is now willing to take steps in a number of areas to put increasing and visible pressure on the North to rein in its provocative actions as well as its blustery rhetoric about nuclear war, and to recommit itself to the agreed goal of denuclearization," he wrote in an assessment published Friday.