The unexpected return of Chinese President Hu Jintao from Italy just hours before the G8-G5 summit was to start on Wednesday has surprised other participating countries and leaders, conference sources said here.
President Hu left for China suddenly on Wednesday as ethnic violence flared in the north-western Chinese province of Xinjiang leaving over 150 people dead.
"The violence has been going on for the last few days there. He has been in Italy since earlier this week. There were no compelling reasons for him to leave now. Chinese Prime Minister Wen Jinbao and other leaders are there to control the situation," a senior delegate at the summit, who requested anonymity, said.
Hu had arrived here at the beginning of this week.
Delegates of the G5, the group of five emerging economies including India, China, South Africa, Brazil and Mexico, said crucial issues like climate change and food security required the presence of the top Chinese leader.
China, one of the fastest growing economies in the world in the last decade, is also considered one of the biggest polluters of the environment along with other developed countries.
Hu was also to attend outreach meetings of the main G8, the group of world's eight most wealthy and industrialized countries, to be held here July 8-10.