Machado had left the country just a month before the US government seized Venezuelan President Nicolás Maduro.

He will be observed to evaluate whether his "psychiatric health is compatible with pursuing his interrogation", authorities said.

The authorities had justified the ban by saying online content was fuelling conflict, while the opposition had condemned it as an abuse of power.

The International Weightlifting Federation becomes the first Olympic federation to choose Russia to host a world championships since its invasion of Ukraine.