A majority of senators in the Democratic Republic of Congo filed a petition to oust the leader of the upper house of parliament on Tuesday, the latest move by allies of President Felix Tshisekedi to weaken his predecessor's lingering power.

In recent months, Tshisekedi has chipped away at the influence of former President Joseph Kabila, with whom he had an awkward political alliance following a disputed 2018 election.

A longtime opponent of Kabila, who governed from 2001-2019, Tshisekedi won office by beating Kabila's chosen successor in a vote observers said another opposition candidate had won.

However, the new president had been forced to bargain over policies with Kabila, who maintained extensive control across state institutions and security services.

More than sixty of the senate's hundred members demanded the resignation of Kabila ally and upper house leader Alexis Thambwe Mwamba in a letter seen by Reuters, addressed to the office of the senate and signed by senator Valentin Gerengo M'vene.

"If those who gave us the mandate decide to withdraw it, I will leave without any problem," said Thambwe, a 77-year-old veteran politician who was most recently minister of justice.

His fall would be the latest setback for Kabila loyalists following the prime minister's resignation in January and the removal of the lower house of parliament's speaker in December.

KABILA RETREATS TO FARM

Tshisekedi, son of longtime opposition leader Etienne Tshisekedi, appears to have blindsided Kabila with his manoeuvring.

Kabila has remained characteristically quiet throughout, retreating to his farm in his political heartland in the south east of the country in December to consult advisers.

"The former president is digesting the various political defeats recorded in recent months, taking time to measure the extent of the damage within his political platform, the Common Front for Congo, which is decaying," said analyst Tresor Kibangula from the Congo Research Group at New York University.

"A crisis cell has been set up for this reason."

The Senate petitioners' letter did not explain why they want to remove Thambwe. However, two senators who asked not to be identified said the move was linked to corruption allegations.

On Tuesday the senate's office turned down a request by the public prosecutor to open an investigation into the withdrawal of three cheques worth more than $3 million on behalf of the senate from the Commercial Bank of Congo on Jan 6., which were later handled by Thambwe.

"These funds went into the treasury. There was no misappropriation on my part," Thambwe said.

Tshisekedi hopes his new coalition, known as the Sacred Union, will give him a more compliant cabinet and legislature that can help push through electoral changes, quell violence in the east and secure funds from the International Monetary Fund.