Chinese artist and dissident Ai Weiwei has confirmed that four of his associates were freed from detention this week, soon after he was released from prison on bail.

Ai was released Wednesday after nearly three months in detention. He is one of the most prominent activists detained in China's crackdown on dissent, which began in February.

Ai's colleagues said the 54-year-old activist confirmed to them Saturday that the four had been released this week.

The terms of Ai's bail prevent him from leaving Beijing or talking to the media.

The official Xinhua news agency said Ai was released because he had confessed to tax evasion and promised to repay what he owes. It also said the diabetic artist was released on medical grounds.

Ai is one of China's best-known artists and an international celebrity. He has exhibited in the world's top art museums and had a hand in designing Beijing's “Bird's Nest” Olympic stadium.

His detention had become an issue in many of China's diplomatic encounters with other countries. The release comes ahead of an important trip to Europe by Premier Wen Jiabao and a high-level U.S.-Chinese diplomatic meeting Saturday in Hawaii.