Chinese President Hu Jintao left Washington Wednesday morning for Brazil, after attending the Nuclear Security Summit.

At the summit, which was aimed mainly at preventing acts of nuclear terrorism, Hu delivered a speech explaining China's policy and practice on nuclear security.

He also put forward proposals on strengthening international cooperation in coping with nuclear security challenges in the world.

"Enhancing nuclear security serves the interest of all countries and requires concerted action," Hu said in his speech.

On the sidelines of the summit, Hu met with U.S. President Barack Obama and the two leaders exchanged views on China-U.S. relations and major global and regional issues of shared interest, and reached important agreement.

"It's a positive and constructive meeting," Ma Zhaoxu, spokesman of the Chinese delegation said Monday when he briefed reporters.

Both sides believe that a good China-U.S. relationship serves the common interests of the two countries and contributes to world peace, stability and prosperity, Ma said.

"It is important for the two sides to work together to increase dialogue, enhance mutual trust and expand cooperation and continue to move China-U.S. relations," he said.

From Washington, Hu is traveling to Brasilia to attend a summit of BRIC countries -- Brazil, Russia, India and China -- and pay a state visit to the Latin American country.

At the BRIC meeting, President Hu and leaders of the other three countries will discuss the global economy and financial situation, issues related to the Group of 20, reform of the international financial system, climate change and cooperation among the four countries, Chinese diplomats said.

After his trip to Brazil, Hu will pay a state visit to Venezuela and a working visit to Chile.