President Hu Jintao of China conferred with South Korea's prime minister on Tuesday during a state visit focused on establishing a new strategic partnership between the Asian neighbors, key players in efforts to denuclearize North Korea.

Hu met South Korean Prime Minister Han Seung-soo to discuss deepening bilateral ties and cooperation on energy and resources, according to Han's office. Hu was also meeting with leading South Korean businessmen.

The meetings came a day after Hu held his third summit this year with South Korean President Lee Myung-bak. The two leaders pledged to expand cooperation in political, economic and other fields — including North Korea's nuclear disarmament.

"We agreed to make joint efforts to ensure the six-party talks process enters a new phase," Hu said Monday, referring to international talks led by China aimed at ending North Korea's nuclear programs.

Hu, speaking at a news conference with Lee after their summit, called for the "full implementation" of the second phase of the denuclearization process that calls for the disablement and declaration of the North's nuclear facilities.

China, North Korea's key ally and main aid donor, has chaired numerous rounds of disarmament negotiations since 2003 on Pyongyang's nuclear programs. The talks — which also involve the United States, the two Koreas, Russia and Japan — have produced a landmark aid-for-disarmament deal.

In June, North Korea demolished its nuclear reactor's cooling tower and submitted its long-delayed nuclear declaration under the deal. The North, however, remains at odds with the US over how to verify the declared nuclear programs.

Pyongyang has accused Washington of delaying its removal from a US terrorism blacklist. Washington has said it will drop North Korea from the list only after it agrees to a full nuclear verification plan.

Lee also requested Hu's cooperation to ensure "North Korean defectors won't be forcibly sent back to the North against their will," Lee's spokesman Lee Dong-kwan told reporters.

China does not recognize North Koreans who enter the country as refugees, rather viewing them as economic migrants. China and North Korea have a treaty that calls for the repatriation of North Koreans caught crossing their shared border without permission. Human rights advocates in South Korea say North Koreans face persecution if they are sent back.

Hu and Lee also agreed on frequent visits by senior officials and to hold the first high-level strategy dialogue by their diplomats within this year, according to a joint statement released after the summit by South Korea.

The two leaders signed several memorandums of understanding on issues such as cooperation in saving energy, high-tech fields as well as trade, according to Lee's office.

Hu was to leave for Tajikistan later in the day to attend the summit of the Shanghai Cooperation Organization, a security forum that includes China, Russia and Central Asian nations.