BEIJING - Chinese Premier Wen Jiabao left Beijing Tuesday morning to attend the upcoming UN Conference on Sustainable Development (Rio+20) in Rio De Janeiro, and pay official visits to Brazil, Uruguay, Argentina and Chile from June 20 to 26.

Wen was invited by Brazilian President Dilma Rousseff, Uruguayan President Jose Mujica, Argentine President Cristina Fernandez de Kirchner and Chilean President Sebastian Pinera.

Rio+20, which will be held from June 20 to 22, also known as the Earth Summit, marks the 20th anniversary of the landmark UN Conference on Environment and Development hosted by Rio in 1992. Wen is scheduled to talk about China's approach to sustainable development at the conference and exchange views with leaders attending the conference.

China hopes the conference will deliver "positive, clear and strong" signals of international cooperation in sustainable development, Vice Foreign Minister Xie Hangsheng Monday told a press briefing in Beijing.

During the four-nation tour, Wen will meet with their leaders to exchange views on bilateral ties, as well as regional and international affairs of common concern, and the visits will bring China-Latin America ties into a new phase of development, according to Xie.