BRUSSELS — The European Union said it will “urgently review” its relations with Egypt as the 28-nation bloc warned that an escalation of violence in the country could have unpredictable consequences.

“Together with its member states, the EU will urgently review in the coming days its relations with Egypt and adopt measures aimed at pursuing” the goals of promoting an “end to violence, resumption of political dialog and return to a democratic process,” EU President Herman Van Rompuy and European Commission President Jose Barroso said today in a joint statement.

“Further escalation must be prevented,” Van Rompuy and Barroso said. “It could have unpredictable consequences for Egypt and for its broader neighborhood.”

The storming of a landmark mosque by the country’s security forces Saturday was the latest in a four-day campaign that has killed at least 800 people and injured thousands, according to the Health Ministry. Security forces yesterday fired tear gas into the al-Fath mosque, where supporters of ousted President Mohammed Morsi had been besieged since Aug. 16.

“Recent developments in Egypt, and more particularly the violence of the last days, are extremely worrying,” Van Rompuy and Barroso said in the statement. “While all should exert maximum restraint, we underline the particular responsibility of the interim authorities and of the army in bringing clashes to a halt. The violence and the killings of these last days cannot be justified nor condoned.”

Senior diplomats from the 28 EU governments will meet Monday to seek to coordinate the bloc’s response and may pave the way to a meeting of EU foreign ministers, according to EU foreign policy chief Catherine Ashton’s office.