Hu Jintao, the Chinese president, on Wednesday cut short his visit to Italy, where he was planning to attend the annual Group of Eight summit of world leaders, three days after the worst ethnic unrest in China since the Cultural Revolution erupted in the Muslim-dominated Xinjiang autonomous region. Mr Hu, who has yet to comment officially on the crisis, had been expected to play a high profile role in this week’s summit, with China pushing for a bigger voice for developing countries in international monetary policy, the FT said.