LONDON — Saudi Arabia has released Prince Mutaib bin Abdullah, the most influential of the hundreds of businessmen and current or former officials detained three weeks ago in an anti-corruption crackdown, an associate of the royal family and an American official tracking the events each said Tuesday.

The release of Prince Mutaib, who had been held along with the others in a five-star Ritz-Carlton hotel in Riyadh, is a sign that the officials leading the crackdown are moving expeditiously to resolve some of the claims. But the kingdom has disclosed almost nothing about the charges against any of the detainees or about any settlement talks with them, so final outcomes, including in the case of Prince Mutaib, may be difficult to discern.

It could not be immediately determined if the prince, 65, was now able to move freely; it was more likely that he had been transferred to some form of house arrest, the American official said. It also could not be determined if he had surrendered any assets in exchange for his provisional release, or whether his assets remained frozen.

A son of the deceased Saudi monarch King Abdullah, Prince Mutaib was once considered a contender for the throne. Until a few hours before his arrest he had controlled one of the three main Saudi armed forces, the national guard. His detention brought the national guard, as well as the internal security forces and the military, all under the effective control of his cousin, Crown Prince Mohammed bin Salman, 32, who is the favored son of King Salman, 81.