(CNN)Lesotho's 80-year-old Prime Minister, Thomas Thabane, says he's no longer "energetic" and will step down in July as the country's leader, his office said Thursday.
Thabane has been under immense political pressure to resign over his alleged involvement in the 2017 murder of his estranged wife.
Thabane, whose official term ends in 2022, said he was leaving office voluntarily and retiring due to old age.
"The job of Prime Minister requires sensory perception as well as rapid and physical strength. Due to my age, I am no longer as energetic as I used to be. As such, I have decided to voluntarily vacate office and hand over the reins of Government in accordance with the laws of Lesotho," Thabane said.
Thabane's former wife, Lipolelo, was shot by gunmen shortly before his inauguration as the prime minister of the tiny African nation. The couple were separated and had been pursuing a divorce before her death.
His current wife, Maesaiah Thabane, has been charged in the murder and has been granted bail. The country's police also sought to charge the prime minister with Thabane's murder, but his lawyers argue he should be granted immunity against prosecution.
Both the prime minister and his wife have not spoken publicly about the allegations.
In April, the Prime Minister deployed the military into the streets to restore order amid unrest in the capital Maseru after he suspended the parliament for three months as lawmakers planned to pass a vote of no confidence in his leadership. A Lesotho court overturned the parliament's suspension, the South African reported.
In the statement announcing his planned exit, Thabane appealed for unity in the mountain kingdom, saying his decision to leave should not be used to score political points.
"To my colleagues in the political arena, this is not the time to divide our nation. This is the time for us to join hands and build our institutions as well as marshal our country to lasting peace and prosperity," Thabane said.