On Friday, European Council President Donald Tusk said that he had invited 27 EU leaders to discuss Brexit on Wednesday on the sidelines of the June 28-29 European Council meeting without the participation of the United Kingdom.
"On Wednesday, the leaders will have to decide what the process will look like, including the date of the next meeting, whether it will take place in July or September," the source said on condition of anonymity.
The United Kingdom is currently struggling with a post-referendum crisis, according to the EU source.
"Everyone understands that there is a substantial crisis in the United Kingdom in the wake of the referendum. This is not only a government and ruling party crisis, which involves Prime Minister David Cameron's resignation, this is much deeper," the representative said.