Recalling the Thursday parade at Tian'anmen Square at the heart of Beijing, UN Secretary-General Ban Ki-moon said what impressed him most was to see the veterans sitting in the marching vehicles as well as their chests "full of medals".

"They are maybe getting old though, but I found that their spirit was still very strong, and their contribution and the sacrifice should never be forgotten," Ban said in a Friday interview with Chinese media in Beijing.

The UN chief noted that the event is also coupled with ceremony commemorating the 70th anniversary of the United Nations' founding in 1945 "from the atrocities and tragedies of second world war".

"The United Nations was established out of such an experience, it is a result of the second world war. So we were committed to that we should not repeat these ... tragic situations. That's why I'm here," he said.

Also in the past 70 years, China has risen from a weak country to the second-largest economy of the world, China "should be very proud", and the pride and achievement "should be accompanied by greater responsibility", Ban said.

He spoke highly of the transcontinental One Belt One Road initiatives, first proposed by President Xi Jinping, as well as the China-led Asian Infrastructure Investment Bank, which are conducive for sustainable development.