Their half-hour meeting, held on the sidelines of the annual Boao Forum here, marked the first face-to-face talks between the premiers of the neighboring countries since June 2016.

It's expected to help revitalize Seoul-Beijing high-level communication that has been relatively in the doldrums amid a row over the deployment of an advanced U.S. missile defense system, THAAD, on the peninsula.

Lee requested closer partnership between the neighbors on joint research on the exact cause of fine dust and joint countermeasures.

In response, Li agreed to strengthen related communication and share experience, stressing the need to bolster cooperation in the environment sector between the two sides.

They also agreed in principle to expand bilateral investment, trade and exchange of tourists.

Li reaffirmed Beijing's commitment to playing a "constructive role" in efforts for denuclearization.

He said, "The realization of denuclearization is China's ultimate goal. (We) hope to maintain communication with South Korea on this matter."

Lee, meanwhile, requested that President Xi Jinping make a trip to South Korea on the occasion of the G-20 summit to take place in Japan in June. (Yonhap)