South Africa and Senegal led efforts on Monday at an African summit to persuade President Robert Mugabe to accept a transitional power-sharing government to defuse the Zimbabwe crisis in the aftermath of Friday’s uncontested polls.

But as African leaders fell behind negotiations and compromise as a way out, the US was preparing to ratchet up pressure on Mr Mugabe by pressing for a vote next week at the United Nations that would impose international sanctions on his regime, including an arms embargo.