Toting sub-machine guns and sometimes wearing masks as they drive along the streets of Uganda, members of an elite military unit are increasingly viewed as a private army to keep 81-year-old President Yoweri Museveni in power - along with his ever-growing family dynasty.

Museveni has led Uganda since 1986, when his rebel forces marched into the capital, Kampala. He has since won four elections - all marred by allegations of violence and rigging.

But this is nothing new in the country - since Uganda gained independence in 1962, power has only ever changed hands through rebellions or military coups.

Museveni is seeking re-election next year and the opposition fears that the Special Forces Command (SFC) could be used to prevent it from campaigning, as it says was the case in 2021.

But the SFC, which for years was commanded by Museveni's son Gen Muhoozi Kainerugaba, has been accused by government critics of abducting, torturing and killing opposition activists all year round, not just during elections. The SFC denies these allegations.

It's like a shadow army within the army which is only answerable to the president and his son. Its rise and influence is causing resentment among senior generals, one military source told the BBC.

This is compounded by the fact that Gen Kainerugaba, 51, who is now the army chief, and has said he wants to succeed his father one day, has enlisted his own son into the army.

Gen Kainerugaba has also been contemptuous of some long-serving generals, calling one a buffoon.

His remarks sent shockwaves through military and political circles, but the government downplayed them as mere social-media banter - something for which Gen Kainerugaba is well known.

Several years ago he made a joke remark about invading neighbouring Kenya, to the dismay of generals.

Analysts say the unit has become so influential that it rivals the power of the regular army, which still has commanders who fought in the guerrilla war that brought Museveni and his National Resistance Movement (NRM) to power.

These observers have raised fears that the two could clash one day - as in Sudan where a civil war has broken out following a power struggle between the army and a paramilitary group once allied with it, the Rapid Support Forces (RSF).

The unit now known as the SFC was established when Museveni first took office, and has a motto stating there is no substitute for loyalty.

The SFC is the most powerful unit within the Ugandan military, comprising the [most] highly trained, best-equipped, and best-funded officers in the country, Dr Gerald Bareebe, a Uganda-born academic based at Canada's York University, told the BBC.

Both the Ugandan army and the SFC declined to comment when approached by the BBC.