The Democratic Republic of Congo has postponed a long-awaited visit to the country by the UN chief and head of the African Union Commission – six month ahead of contentious elections.

The trip by Antonio Guterres and his AU counterpart Moussa Faki Mahamat was cancelled this week as it was “untimely” but they would be welcomed at a “time convenient for all”, the government said.

A separate visit from the US ambassador to the UN, Nikki Haley, was also delayed.

Observers say President Joseph Kabila is a discreet man who doesn’t like public meetings.

Many in the capital, Kinshasa, see the delays as a sign of further uncertainty about the polls – but the UN brushed aside concerns about the postponement.

International and regional powers are pressing for free and fair elections on 23 December – which are to take place two years after President Kabila’s term in office expired.

While he is meant to step down, Mr Kabila has not made a formal announcement that he will not be seeking another mandate.

Presidential hopefuls are due to announce their candidacy by 8 August. The authorities have repeatedly said elections will go ahead as planned and that the president will respect the constitution.

At a recent event in Kinshasa, a representative from the US embassy told a crowd:

"I think President Kabila can become a hero in Congolese history, which he will do in shaping, in December of this year, the first peaceful, credible and democratic transfer of power from his country."

A diplomatic source told the BBC the postponement was a sign of DR Congo’s isolation - so it seems all official visits are likely to be off until Mr Kabila announces his intentions.