Celebrated artist Ai Weiwei is at home on probation after almost three months in Chinese detention, but says he cannot discuss his case.

The outspoken 54-year-old activist offered apologies to reporters and television crews who gathered outside his suburban Beijing studio following his release Wednesday.

Ai said he is in good health and happy to be home. But he begged the reporters to understand that he cannot give any interviews because of the situation he is in.

Ai was arrested in early April at the height of a crackdown on Chinese dissidents and activists, possibly prompted by fears of Middle East uprisings spreading to China. Weeks after the arrests, Beijing announced he was being held for tax evasion.

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.

The release was immediately welcomed by foreign governments and in the international art community, though many urged that diplomatic pressure be maintained until Ai is cleared of all charges. Rights groups believe the real reason for Ai's arrest was his repeated criticism of government policies.

German Chancellor Angela Merkel called the release just a first step toward clearing up the charges against Ai. Amnesty International warned that he must not be put under illegal house arrest like many other Chinese dissidents.

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.