GOMA, Congo (Reuters) - A Congolese colonel who threatened to overthrow President Joseph Kabila has been detained in Tanzania, and Congo is seeking his extradition, Congo’s defense minister said on Wednesday.

John Tshibangu, who had been based in the lawless east of the Democratic Republic of Congo (DRC), this month issued a video “hereby giving 45-day notice to Kabila to step down from power ... (or) we are going to take Kabila down”.

“I am ready to take up arms and fight ... the dictator who has killed our compatriots in the Kasai region and in the east,” he said. It was unclear what firepower or manpower he had to back up his statement.

Defence Minister Crispin Atama Tabe said Tshibangu was being held but did not give further details.

“If the extradition request does not succeed, the DRC may request him to be tried in Tanzania, but for now Congolese military justice ... is working (on) his extradition,” he said.

Tanzanian authorities did not immediately respond to a request for comment.

Tshibangu was once a military commander in the central Congolese region of Kasai, but defected in 2012 and moved eastwards.

Kabila’s refusal to step down when his mandate expired in December 2016 has emboldened several armed groups, raising the prospect of the vast, mineral-rich nation sliding back into the kind of warfare that killed millions in the 1990s, mostly from hunger and disease.

As well as rebel groups in the east, fighting between ethnic militia and government forces in Kasai region - not thought to have anything to do with Tshibangu - has killed thousands of people and displaced more than three quarters of a million.