The US embassy in Cairo has warned its nationals of the possibility of clashes in Cairo near the two sit-ins being held by supporters of ousted president Mohamed Morsi.

In a statement issued on Wednesday, the embassy announced that the Egyptian government had stated its intention to disperse the sit-ins in Nasr City's Rabaa Al-Adawiya Square and Giza's Al-Nahda Square.

Clashes are expected to erupt when the sit-ins are dispersed, said the statement.

The warning comes after Egypt's presidency announced on Wednesday that talks between foreign envoys and the Muslim Brotherhood have failed, adding that the Brotherhood and its allies bear "full responsibility for the failure and what will follow."

Talks have been ongoing in recent days between the military-backed government and senior figures within the Muslim Brotherhood to find a solution to the political deadlock that has gripped Egypt since the ouster of the Brotherhood’s Morsi on 3 July.

The embassy advised its nationals to avoid all areas of protest, stating that peaceful demonstrations could easily escalate to violence.

Meanwhile, the US State Department said on Wednesday as international envoys returned home that ending Egypt's political crisis would require compromise.

"We believe that any solution will require both sides to make compromises," said US State Department spokesperson Jen Psaki told a press conference on Wednesday. "These decisions can only be made by Egyptians for Egyptians. We certainly hope they will make them soon," she added.

Psaki said Washington was concerned about the presidency’s announcement that talks had failed, adding: "Now is not the time to assess blame but to initiate a dialogue that can help restore calm for the long term."