BEIJING, Oct. 13 -- A top US space expert spoke highly of yesterday's mission and called for increased space programme co-operation between the United States and China.

"It's a demonstration. The launch of the Shenzhou VI manned spacecraft clearly demonstrates China's consistent presence in space," said Joan Johnson-Freese, a professor who heads the Department of National Security Studies at the US Naval War College.

"As to manned space exploration, China is catching up with the United States quickly," she said.

Johnson-Freese is widely acknowledged for her advocacy of US space exploration. Her book on China's space programme and dozens of research papers have made her a top US observer on the subject.

A member of the US National Research Council and a senior adviser to the US Congress on space strategy, Johnson-Freese refuted suggestions that China's space exploration would become a threat to the United States.

The expert urged closer co-operation between the United States and China in space exploration, saying it is in the interests of both nations.

Leroy Chiao, US astronaut with Chinese ancestry, told China Daily yesterday: "This successful second launch demonstrates that China is serious about space exploration and has the technical expertise to execute and sustain a manned space programme."

Russia also hailed the launch and said it looked forward to working with China on future programmes.

"Another power has joined the space club," Nikolai Moiseyev, deputy head of the Russian Space Agency, was quoted by ITAR-TASS news agency as saying after the launch.

Belgian astronaut Frank de Winne yesterday wished Chinese astronauts a smooth journey.

De Winne, from the European Space Agency, is the fourth European astronaut to stay aboard the International Space Station.

The success of the mission will not only promote China's development but also be a great contribution to mankind, de Winne said.

Maria Margarete Gosse, spokeswoman for the German Embassy in Beijing, congratulated China on the launch of the historic space mission.

"We are following the latest progress of China's space exploration programme with great interest," she said, wishing China "all the best" for the successful completion of the mission.

Sanjay Verma, information and culture counsellor of the Indian Embassy in Beijing, conveyed his government's congratulations to the Chinese Government and its people on the significant achievement.

"We rejoice in the successful launch of Shenzhou VI," he said.

Hong Kong Chief Executive Donald Tsang said yesterday in Hong Kong,"We will try to invite the two astronauts to visit Hong Kong. I sincerely hope that we can make it."

The country's space experts said the launch demonstrated that China has the ability to conduct manned space flights.

"Compared with the landmark launch of Shenzhou V, piloted by astronaut Yang Liwei two years ago, the country's second manned space flight goes further in space explorations," said Hou Xiufeng, a senior space engineer with the China Aerospace Science and Industry Corporation.

"This flight is helpful towards the goal of building a space station in the future."

Wang Yongzhi, chief designer of China's Manned Space Programme, was quoted by Xinhua News Agency as saying: "This is an important step towards the ultimate success of the nation's manned space flight project."

Yang Liwei, the first Chinese to orbit the Earth when he went aboard Shenzhou V for 21 hours on October 15-16, 2003, told reporters yesterday that the two astronauts performed well.

"I'm sure they will do better than I did. I was alone," Yang said after seeing the launch at the Jiuquan Satellite Launch Centre in Northwest China's Gansu Province. "They are a duo supported by better technology."