Chinese President Hu Jintao on Friday called on media organizations around the world to contribute to building a harmonious world when they are facing unprecedented opportunities and challenges.

Hu made the remarks in a speech at the opening ceremony of the World Media Summit, which gathered about 300 representatives from more than 170 media outlets from around the world.

He said the world is in a period of great development, major transformation and extensive readjustment. Multi-polarity and economic globalization are developing profoundly, and worldwide exchanges of ideologies and cultures are becoming more frequent and active, with closer interconnections among nations.

The president also reminded the audience of the challenges the world faces, including the continuing impact of the global financial crisis, growing imbalance in development, climate changes, food security and energy resources security, as well as terrorism, cross-nation organized crime, major infectious diseases and other threats in non-conventional security areas.

"Unstable and uncertain factors are increasing. There are many challenges to world peace and development," he said.

"Facing unprecedented opportunities and challenges, media organizations around the world should conform to the trends of the times, go forward together, and strive to contribute to building a harmonious world with lasting peace and common prosperity," said Hu.