Late October -EU diplomats and officials expect an extraordinary summit of EU leaders before Oct. 31.

For now, the 27 are not planning to organise an extraordinary summit on Brexit in November, the official said.

The African Union was scheduled to have an extraordinary summit in Johannesburg next month to finalise all these elements.

It remains uncertain whether EU leaders would hold an extraordinary summit to approve sanctions or whether governments could approve the decision in writing.

Some diplomats said Nov. 13 was one date under consideration for the extraordinary summit, though others said it was still a moving target.

The body announced the " extraordinary summit" only on Monday and southern African leaders have scrambled to change schedules to consider Zimbabwe's crisis.

Havasi added that leaders of the Visegrad Four countries, Poland, the Czech Republic, Slovakia and Hungary will hold an extraordinary summit in Prague on Friday.