President Hu Jintao, on an official visit to Italy for the G8 summit, has decided to return to China due to the situation in Xinjiang where riots have claimed more than 150 lives, ANSA news agency reported early Wednesday.

"Given the worsening of the disorder in Xinjiang, President Hu Jintao has decided to move forward his return to China and not participate in the G8 summit" which opens Wednesday in the central Italian town of L'Aquila, Tang Heng, first political counsellor at the Chinese embassy in Rome, was quoted as saying.

Hu, visiting Pisa in Tuscany, "is leaving this town to return to Beijing," the Italian news agency said.

State Councillor Dai Bingguo would take part in the summit of the Group of Eight and major developing countries on Hu's behalf, China's official Xinhua news agency reported.

Fresh ethnic strife erupted in Urumqi, capital of China's remote northwest Xinjiang region, on Tuesday as thousands of angry Han Chinese armed with poles, meat cleavers and other makeshift weapons stormed through the streets as the flashpoint city riven by ethnic tensions descended into chaos.

Heavily armed security forces fired tear gas at the crowds and ordered a night curfew in an effort to restore calm in Urumqi, where 156 people died in weekend clashes.

G8 leaders gathering in Italy Wednesday faced deepening crises in Iran and China and a warning that the worst political and social effects of the global economic downturn are still to come.

Leaders of the Group of Eight (G8) industrialised nations and a host of emerging powers meet until Friday in the city of L'Aquila, which was devastated in April by an earthquake that killed nearly 300 people.