Somalia has declared AU envoy Simon Mulongo a persona non grata, and ordered him to leave the country within seven days.
Mr Mulongo is the Deputy Special Representative of the African Union (AU) for Somalia.
He is accused of engaging in activities that were incompatible with the mandate of Amisom (African Union Mission in Somalia) and the country's security strategy, state-owned Somali National TV (SNTV) tweeted on Thursday.
A separate statement posted on the station’s Twitter account said: "The minister of foreign affairs, Mohamed Abdirisak, said that Somalia will hold accountable Amisom personnel, particularly those at the leadership level, who are expected to be beyond reproach in their integrity as they discharge their duty under the UN/AU mandate."
According to privately-owned Radio Risala, the expulsion of the ex-Ugandan MP could be linked to a standoff in the country over Amisom's future plan which has been controversial in recent months.
In January 2019, the Horn of Africa nation declared Nicholas Haysom, Special Representative of the United Nations Secretary-General for Somalia, a persona non grata after he asked the government to provide an explanation about the detention of ex-al-Shabab deputy leader, Mukhtar Robow.