Western diplomats warned of "growing insecurity" in Kenya ahead of Thursday's presidential election re-run, boycotted by the main opposition.
Inflammatory rhetoric and attacks on the election commission made it more difficult to hold a legitimate poll, the 20 envoys said.
Meanwhile, Kenyan prosecutors said opposition leader Raila Odinga's sister would be charged with inciting violence. He vowed to disrupt Thursday's poll with a mass protest.
According to Odinga, the vote cannot be held before key reforms, including the sacking of Independent Electoral and Boundaries Commission [IEBC] officials, are implemented.
About 70 people have been killed in violence since the IEBC declared President Uhuru Kenyatta the winner of elections on 8 August.
The Supreme Court of Appeal annulled his victory, saying the poll was marred by irregularities and illegalities. However, Odinga says nothing has changed since.
The foreign envoys said they were concerned about the "deteriorating political environment" in East Africa's biggest economy.
"It is easier to tear down than to build up. But it is dangerous, and it must stop," US ambassador Bob Godec said in a statement on behalf of the 20 diplomats, including those of France, Germany and the UK.
Last week, a senior member of the IEBC fled to the US amid death threats.
Roselyn Akombe said the commission was under political "siege", unable to reach consensus or take any decisions.
The fresh ballot papers are ready for distribution and the technology is apparently all set for a re-run, but there are still doubts about whether it will go ahead - and if it does, whether it will be seen as legitimate.
The opposition reaffirmed that Odinga will not take part in the poll. The governing Jubilee Party has said the election will go ahead and is calling on Kenyans to come out and vote.
According to the constitution a re-run must be held before 1 November, but a flurry of court challenges, the resignation of an electoral commissioner and threat of a controversial new electoral bill being signed into law leave many uncertainties.
Source: News Agencies, Edited by website team