Chinese President Hu Jintao cut short his stay in Italy after concluding a state visit to the country and left for home early Wednesday due to the situation in northwest China's Xinjiang Uygur Autonomous Region.
State Councilor Dai Bingguo will attend the summit of the Group of Eight and major developing countries later this week in the central Italian city of L'Aquila on Hu's behalf.
The date for Hu's state visit to Portugal will be fixed by the Chinese and Portuguese sides some time later.
Hu arrived in Rome on Sunday for a state visit at the invitation of Italian President Giorgio Napolitano. He was originally scheduled to attend the summit of the Group of Eight and major developing countries and pay a state visit to Portugal.
During the visit, Hu held talks with Napolitano, and met with Italian Prime Minister Silvio Berlusconi and parliament leaders on bilateral relations.
At least 156 people were killed during a riot Sunday evening in Urumqi, capital city of Xinjiang. More than 1,000 others were injured.
Police in Xinjiang have said they have evidence that the separatist World Uyghur Congress led by Rebiya Kadeer masterminded the riot.