KAMPALA: Ugandan police on Thursday detained a former prime minister who last month announced he would seek the presidency amid a political dispute with the country's long-serving leader.

Amama Mbabazi was arrested as he traveled from the Ugandan capital, Kampala, to a town in eastern Uganda where he planned to consult with his supporters. Police had warned he faced arrest if he proceeded with the trip without first getting the support of the ruling party, of which he is a member, but Mbabazi insisted that as a presidential aspirant he needed no one's approval to consult across the country.

Police took "preventive action" against Mbabazi, Andrew Felix Kaweesi, an assistant inspector general of police, told reporters Thursday.

"He is now under incarceration," Kaweesi said.

The arrest of Mbabazi, a former ally of long-serving Ugandan President Yoweri Museveni, could stoke political tensions here as Museveni tries to remain the undisputed leader of his party. Museveni has led Uganda since taking power by force in 1986.

Mbabazi was a supporter of Museveni's former rebel movement and was once seen as a possible successor to Museveni after holding several Cabinet positions over the years. Museveni fired Mbabazi as his prime minister last year amid reports Mbabazi was exploring a possible presidential run.

After Mbabazi announced last month that he would seek the presidency as a member of the ruling party, he was denounced by party officials who want Museveni to run unopposed.

Ugandan police on Thursday also detained opposition leader Kizza Besigye, who planned to address two rallies, said his aide Francis Mwijukye.