(AFP) - Two decades of attacks on Rwanda's opposition, journalists and rights groups have created a "climate of fear" ahead of next month's presidential election, Amnesty International warned Friday.

"Since the ruling Rwandan Patriotic Front (RPF) took power 23 years ago, Rwandans have faced huge, and often deadly obstacles to participating in public life and voicing criticism of government policy," said Muthoni Wanyeki, Amnesty's regional director for East Africa, the Horn and the Great Lakes.

"The climate in which the upcoming elections take place is the culmination of years of repression."

The rights group released a 30-page report detailing several alleged violations, including the killing of an opposition party member as well as harassment and intimidation against those planning to run in next month's vote.

Critics of the government of President Paul Kagame have been "jailed, physically attacked -- even killed -- and forced into exile or silence," the London-based Amnesty said.

Since the end of the 1994 genocide in which around 800,000 mostly Tutsi people died, Rwanda has been praised for its stability and economic performance. However, it often comes under fire for a lack of political freedom.

Rwanda is constitutionally a multi-party system but there is practically no opposition within the country.

All recognised parties generally support the policy decisions made by the RPF -- with the exception of the small Democratic Green Party which was the only one to object to 2015 constitution changes allowing Kagame to seek re-election.

As of last month, only four candidates had declared their intention to run against Kagame in the August 4 polls.

Kigali's election committee is due to release a final list of candidates on Friday.

Kagame has been in charge since taking power at the head of a rebel army in 1994 and has already served two seven-year terms as president.

"Rwanda's history of political repression, attacks on opposition figures and dissenting voices in the context of previous elections stifles political debate and makes those who might speak out think twice before taking the risk," said Wanyeki.

"Killings and disappearances in 2017 need to be placed in the context of many years of similar violence for which no one has yet been held to account."

© Agence France-Presse