Ugandan President Yoweri Museveni has fired his prime minister, a former ally who has emerged as a potential challenger to the veteran leader.

Prime Minister Amama Mbabazi was the only cabinet member affected by a reshuffle announced late on Thursday, Ofwono Opondo, a spokesman for Uganda's government, said. The prime minister was replaced by Health Minister Ruhakana Rugunda.

Mbabazi had enjoyed a close relationship with Museveni, aged 69 and Uganda's leader since 1986, but ties between the two became strained recently, with Museveni accusing Mbabazi of taking decisions in the ruling party without consulting him.

In a letter to parliament announcing the sacking, Museveni only thanked Mbabazi for "the contribution he has made to his country" but gave no further explanation.

Mbabazi is one of the most senior members of the ruling party, the National Resistance Movement, and had been widely expected to seek the presidency in elections in 2016, though he has not confirmed that.

Succession speculation

New Prime Minister Rugunda is one of Museveni's closest allies, and has in the past served as minister for health, the interior and foreign affairs.

President Museveni has given little hint about his preferred choice in the event of retirement [AP]

Some members of the ruling party are openly urging Museveni to retire, although some loyalists insist Museveni remains popular across the country and want him to stay in office.

Despite widespread speculation about Museveni's likely successor, the president has given little hint about his preferred choice in the event of retirement. The rapid promotion of his son, Brigadier Muhoozi Kainerugaba, within the ranks of Uganda's military has fuelled concern that Museveni is grooming his son to take over, charges denied by the presidency.

Museveni's close allies earlier this year passed a resolution designating him as the ruling party's sole candidate for the top job.

After he seized power in 1986 following a guerrilla war, Museveni said he would not rule like some African leaders who kept power for too long.

He has since fallen out with some of his former comrades, including opposition leader and three-time presidential challenger Kizza Besigye, who accuse Museveni of straying from the ideals that led them to wage a war against dictatorship.

Source: Agencies