The president's son, Muhoozi Kainerugaba, 52, is currently head of the army, and wields huge and growing influence as his 82-year-old father plays a declining role in governing the east African country after four decades in power.
"Muhoozi", as he is widely known, has vowed to run in the next presidential election scheduled for 2031, but many are unnerved by his flouting of the law, and inflammatory posts on social media, where he frequently boasts of torturing opponents in his "basement".
In recent months, he has had political rivals imprisoned, threatened to behead opposition leader Bobi Wine, and forced the closure of the country's leading independent media group for several weeks.
Although Museveni has ruled with an iron grip since 1986, many within his party, the National Resistance Movement (NRM), have voiced concern at the apparent moves to hand power to his son.
In a closed-door meeting of the NRM's executive committee on Tuesday, convened to determine a successor, a vote on the son's candidacy had to be abandoned as several of the 28 members spoke against the plan and received loud cheers, according to five people present.
Four people had voted in favour of the son, three had voted against, by the time the vote was called off, the sources told AFP.
