Ugandan riot police patrol on the streets of the Kamwokya neighbourhood in Kampala where pop star-turned-opposition lawmaker Bobi Wine, whose real name is Kyagulanyi Ssentamu, has his recording studio and many supporters. Picture: Ronald Kabuubi/AP

Kampala, Uganda - Ugandan security forces took pop star and opposition lawmaker Bobi Wine into custody when he arrived from the United States on Thursday, angering his supporters while authorities barred public gatherings they said threaten public order.

The singer was "unlawfully detained by military officers" on arrival, his U.S.-based lawyer Robert Amsterdam said on Twitter. National police chief Okoth Ochola said on Twitter that he was being taken to his home but was not under arrest.

Police set up barriers near the airport and elsewhere around the capital, Kampala, amid heavy security. Police detained the singer's brother and at least two other people who were driving to the airport, without explanation, lawyer Asuman Basalirwa said.

The singer, whose real name is Kyagulanyi Ssentamu, has

Ssentamu had sought treatment in the U.S. for injuries allegedly sustained during state torture, which Uganda's government denies.

Police had said only family members would be permitted to meet the singer. His arrival was not broadcast by local stations NBS and NTV, which often air live coverage of such events.

Another of the singer's lawyers, opposition legislator Medard Sseggona, said he had escaped police detention at his home. Police also surrounded the home of the mayor of Kampala, Erias Lukwago, and he was unable to leave, Sseggona said.

A musician and supporter of pop star-turned-opposition lawmaker Bobi Wine, whose real name is Kyagulanyi Ssentamu, walks past Wine's recording studio in the Kamwokya neighbourhood in Kampala where he has many supporters. Picture: Ronald Kabuubi/AP

Ssentamu, who won a national assembly seat last year, faces treason charges over his alleged role in an incident last month in which the president's convoy was pelted with stones. He denies wrongdoing. His next court appearance is Oct. 1.

The 36-year-old Ssentamu says he is fighting for freedom from oppression and wants Museveni, in power since 1986, to retire. Museveni in turn has accused opposition figures of trying to lure Uganda's large youth population into rioting.

Ssentamu has a big following among poor, unemployed young people in urban areas. His arrest sparked riots by demonstrators demanding his release and security forces violently put down protests in the capital.

Dozens of global musicians have condemned the treatment of the singer, and the European Union parliament and some U.S. senators have urged Ugandan authorities to respect basic human rights.

Museveni, a key U.S. ally on regional security, took power by force and has since been elected five times. Although he has campaigned on his record of establishing peace and stability, some worry those gains are being eroded the longer he stays in power.