WASHINGTON -- The just concluded fifth round of annual Strategic and Economic Dialogue between the United States and China have shown a commitment from both sides to broaden the dialogue, a US expert said Friday.

Besides real progress in areas such as investment and climate change, the US and Chinese sides have shown commitment to " sustain and to broaden what goes on within these dialogues," Jonathan Pollack, director of the John L. Thornton China Center at Brookings Institution, told Xinhua in an interview.

He stressed the importance of the commitment at the senior level, saying that "because without a commitment in both leaderships to sustain these processes, momentum and progress will stall very quickly."

Pollack said meetings on the economic track saw more tangible results, while the strategic security talks were more vague in its outcome.

However, new issues or issues previously not extensively discussed are now being raised at the strategic track, such as cyber security, situation on the Korean Peninsula, as well as questions related to US ballistic missile defense policy, he said.

"The good news is these meetings not only were held, but I think there were some very candid discussions on these topics," said Pollack, adding the two sides have to find a way to sustain these process in different working group endeavors.

As more and more issues are being included in the talks, disagreements arise inevitably.

Pollack said the solution to the problem was well captured by Vice-Premier Wang Yang, who co-chaired the dialogue for the Chinese side, in a Thursday dinner speech.

"He didn't go to great detail about the discussions, but he was acknowledging openly that the two countries have different conceptions often, and we shouldn't be afraid to air those differences," said Pollack.