Lesotho's Prime Minister Thomas Thabane will be charged with the killing of his estranged wife, the deputy police commissioner has said.

The prime minister will appear at the Maseru Magistrates Court on Friday "to face a murder charge in connection with the killing of Lipolelo Thabane", Deputy Commissioner of Police Paseka Mokete said on Thursday.

More:

The 80-year-old Thabane took to the radio to announce he would step down at the end of July but chose not to mention the murder case. He cited old age as a reason for quitting as leader of the tiny, mountainous territory encircled by South Africa.

"I have served my country diligently," Thabane said. "I've worked for a peaceful and stable Lesotho. Today ... at my age, I have lost most of my energy ... I hereby retire as prime minister with effect from the end of July."

Thabane had been under mounting pressure over the death of former First Lady Lipolelo, who was shot dead in June 2017 near her home in the capital, Maseru, two days before he took office.

Wife implicated

The prime minister's current wife, Maesaiah Thabane, was arrested this month and charged with ordering the murder but is currently out on bail.

Both she and Thomas, who married two months after Lipolelo's killing, have denied any involvement in her death.

Thabane's spokesman Relebohile Moyeye told Reuters News Agency he could not comment because he had not yet seen the police charges.

Lesotho police claim Maesaiah hired hitmen to kill Lipolelo and was not actually present at the shooting herself.

Lipolelo, then 58, and Thabane were going through an acrimonious divorce at the time. An unknown assailant shot her dead in her car.

Her friend, Thato Sibolla, who was travelling with her in the vehicle, escaped with gunshot wounds and has since fled to neighbouring South Africa fearing for her life.

Forced to resign

The prime minister's resignation comes days after his party's executive council called for him to step down immediately, saying he cannot stay in office with the murder charge hanging over his head.

Thabane's re-election in 2017 had brought hopes of stability to Lesotho, a country with a long history of turmoil.

He first came to power in 2012 as head of the country's first coalition government, formed after an inconclusive vote.

However, his second term was rocked by Lipolelo's murder and ructions in the governing party.