BEIJING (Yonhap) -- The top nuclear envoys of the United States and China held in-depth talks last week, bridging their differences on ways to resume long-stalled nuclear talks with North Korea, according to China's foreign ministry Monday.

China's foreign ministry spokesman Qin Gang made the remarks three days after U.S. Special Representative for North Korea Policy Glyn Davies held three rounds of talks with his Chinese counterpart Wu Dawei in New York and Washington last week.

Asked about China's assessment about last week's talks between Davies and Wu, Qin replied, "The two sides have expanded consensus and narrowed differences."

"They had in-depth exchanges on views on safeguarding peace and stability on the Korean Peninsula, realizing denuclearization and resuming the six-party talks," Qin said during a regular press briefing.

Fresh diplomatic efforts have been under way among South Korea, the U.S., Japan and China to resume the six-party negotiating forum amid threats by North Korea to carry out a "new form" of nuclear test ahead of visits by U.S. President Barack Obama to South Korea and Japan this week.

"China is ready to maintain communication and consultation with all relevant parties, including the United States, and play a constructive role to promote peace talks," Qin said.

Earlier last week, a diplomatic source with knowledge of the matter told Yonhap News Agency that South Korea, the U.S. and Japan have agreed to lower the bar on conditions to reopen the six-party talks.

According to the source, the six-nation talks aimed at ending North Korea's nuclear program can re-open if Pyongyang reaffirms its 2012 aid-for-disarmament deal with the U.S.

The new condition was part of an agreement reached at a trilateral meeting of the top nuclear envoys of South Korea, the U.S. and Japan in Washington earlier this month.

The three envoys listed steps North Korea should take to resume the six-party talks that involve the two Koreas, the U.S., China, Japan and Russia. The conditions, the source said, are the same as those set in the February, 2012 deal between North Korea and the U.S.

Under the so-called "Leap Day" deal with the U.S., North Korea promised to suspend nuclear and long-range missile tests and allow international inspectors to monitor its nuclear sites in exchange for food aid.

The deal fell apart two months later when North Korea launched a long-range rocket and conducted its third nuclear test a year later.

Subsequently, South Korea, the U.S. and Japan had raised the bar for North Korea to rejoin the six-party forum by demanding that the communist country take additional denuclearization measures beyond what it had promised in the "Leap Day" deal.

Now, the U.S. and its Asian allies have apparently eased their conditions for North Korea back to the level of the 2012 deal, the source said.

Meanwhile, a South Korean military source said Monday that increased activities, including a rise in movements of vehicles, had been observed at North Korea's nuclear test site of Punggye-ri.

But, there have been no signs that a fourth nuclear test is imminent, the source said.