Lesotho’s Senate has passed constitutional amendments seeking to curb the prime minister’s power to dissolve Parliament and call for a fresh election, the latest episode in an extraordinary political saga that has gripped the tiny mountain kingdom.

The move by the legislative body on Tuesday came as Prime Minister Thomas Thabane faces mounting pressure to resign from his post.

Thabane has been under pressure to step down due to a murder case in which he and his current wife are suspected of involvement in the 2017 assassination of his estranged, previous wife, Lipolelo Thabane, in 2017. They both deny this.

The 80-year-old prime minister has promised to step down in July due to old age but his political opponents including rivals within his ruling party want him to leave immediately – but Thabane has so far shown no signs of leaving early to defuse the crisis.

In March, he suspended the Parliament for three months shortly after the lower house National Assembly passed a bill barring him from calling fresh elections if he loses a looming no-confidence vote. However, the country’s constitutional court last week overturned his decision, bringing closer the possibility of a no-confidence vote.

A day later, on April 18, Thabane sent troops onto the streets of the capital, Maseru, to “restore order”, accusing unnamed law enforcement agencies of undermining democracy. The army withdrew the following day.

South Africa, which entirely surrounds Lesotho, dispatched over the weekend a delegation to Lesotho for high-level talks aimed at calming the situation. In a joint statement, mediators said the coalition government and other stakeholders had agreed to guarantee a “dignified, graceful and secure” exit for Thabane. The prime minister, however, hit back, saying he would not be told when to leave office.

Many analysts have predicted that Thabane’s next move would be to advise King Letsie III to dissolve Parliament, which the law allows.

But the latest constitutional amendments prohibit current and future prime ministers from advising the king to dissolve Parliament, unless a majority of legislators support the move.

The new amendments passed by the 33-member Senate seek to limit the power of prime ministers while giving Parliament a more meaningful role in its own dissolution.

“What happens now is for the amendment to be taken to the speaker of the National Assembly who will then pass it on to His Majesty for endorsement as a law,” explained Advocate Lekhetho Rakuoane, the leader of the opposition Popular Front for Democracy and mover of the amendment.

Before being debated in the Senate, 93 legislators of the 120-member National Assembly voted for the bill.

It also provides a mechanism for the appointment of a new prime minister should they die or resign unexpectedly.