The US has warned President Paul Kagame that he faces instability and uncertainty if he presses ahead with plans to change the constitution of Rwanda to allow him to stay on for a third term.
Mr Kagame was once hailed as part of a new generation of African leaders, helping usher in democracy after taking de facto power at the end of the country's bloody civil war in 1994.
Tony Blair is among his advisers on governance.
However, he has been criticised repeatedly for stifling opposition, interfering in neighbouring countries affairs – including the long-running conflict in the Democratic Republic of Congo where more than five million people have died – and trying to cling to power.
In July, parliamentarians voted in favour of changing the constitution to allow Mr Kagame to stay on for a third term. He has now set up a constitutional commission to review the country's two-term limit.
John Kirby, spokesman for the State Department, called on Mr Kagame to honour his previous commitment to respect term limits.
“We do not support those in positions of power changing constitutions solely for their political self-interest,” he said.
Mr Kagame has fallen from international favour since the days when he was seen as the hero who led Rwanda's Tutsis to victory over the genocidal Hutu onslaught.
In June General Karenzi Karake, his head of security, was arrested in the UK over alleged war crimes in the aftermath of the 1994 genocide. He was eventually released after a court decided he could not be extradited to Spain.
Now he is the latest African leader to be accused of "stayism".
It follows unrest in Burundi where President Pierre Nkurunziza won a third term earlier this year. More than 100 people have died in the violence amid protests that his run was unconstitutional.
Barack Obama seized on the issue during his African visit in July.
“When a leader tries to change the rules in the middle of the game just to stay in office, it risks instability and strife, as we’ve seen in Burundi,” he said in Ethiopia. “And this is often just a first step down a perilous path.”