Ugandan pop star-turned-MP Robert Kyagulanyi, known as Bobi Wine, has landed at the Entebbe International Airport where security agents have separated him from other passengers and taken him away.
It is not clear if they are detaining him or escorting him to his home.
Speaking in Nairobi, Kenya earlier, before boarding a flight to Uganda, Mr Kyagulanyi said he was afraid of returning home "because of the way the government is conducting itself".
"I'm feeling better and I hope to recover slowly by slowly. I'm going back, although the situation back home is uncertain," he said at Nairobi's Jomo Kenyatta airport.
"The government is evidently panicking because they've never seen so many people united and speaking with one voice," he added.
Roads had been sealed off and barricades erected around the airport ahead of his return.
There's a tight armed police cordon around the airport, with helicopters circling overhead.
At his home in Magere, on the outskirts of the capital Kampala, police is also heavily deployed.
Mr Kyagulanyi had been in the United States where he was seeking specialised treatment for injuries that he alleges he got when tortured in custody.
Bobi Wine is facing charges of treason relating to an alleged attack on the convoy of President Yoweri Museveni during a by-election campaign.
Meanwhile, his supporters may have been banned from the country's airport, but a small group of them have been spotted outside his home.