President Lee Myung-bak returned home on Friday (May 30) night after winding up his four-day state visit to China, which was capped off by his surprise visit to the earthquake-stricken southwestern Chinese province of Sichuan.

Lee held talks with Chinese President Hu Jintao shortly after his arrival in Beijing on Tuesday, and the two leaders agreed to upgrade bilateral relations from their previous "comprehensive cooperative partnership" to a "strategic cooperative partnership."

The upgraded bilateral relations, formally announced in a joint statement on Wednesday after Lee’s talks with Chinese Prime Minister Wen Jiabao, call for significant improvement in exchanges along with cooperation in diplomacy, security, economy, social issues and culture. The statement also encompassed almost all aspects of Sino- Korean relations, as well as regional and global issues.

In a show of his genuine intention to improve relations with China, Lee flew to Chengdu, the capital of Sichuan Province, earlier on Friday after inspecting South Korean-invested companies in Qingdao, a major seaport and industrial center in the eastern Chinese province of Shandong.

Lee, accompanied by Korean Foreign Minister Yu Myung-hwan, Chinese Foreign Minister Yang Jiechi and other top officials from both countries, traveled for an hour by bus to Dujiangyan, a remote city in Sichuan Province severely damaged by the magnitude 7.9 earthquake on May 12.