Unidentified gunmen attacked the Republican Guard officers’ club in Egypt, killing 16 people, medical sources said, amid reports that army killed at least 16 Islamist activists during a protest on Monday.

“A group of armed terrorists tried to break into the Republican Guards’ headquarters on Monday,” the Egyptian army said in a statement.

A security source said that around 200 armed members of the Muslim Brotherhood were arrested in the attack on the Republican Guards’ headquarters.

Earlier, the country’s state TV had reported that unidentified gunmen attacked the key army headquarters, killing at least one and injuring 40 people.

Meanwhile, the Muslim Brotherhood said that 16 of its supporters were shot dead during a protest in Cairo in favor of reinstating Islamist President Mohammed Mursi.

“Sixteen people were killed and 100 others injured, many of them in serious condition,” the party’s spokesman, Ahmed Ared, told AFP

The protest took place outside a key army headquarters, where – according to AFP – reporters were not allowed access.

The army reportedly fired tear gas canister and bullets in the air to disperse the crowd. AFP quoted one protesters as saying that men in civilian clothing attacked the demonstrators.

“The Republican Guard fired tear gas but the thugs came from the side. We were the target,” the protester told AFP.

Supporters of Mursi – who hails from the Muslim Brotherhood – have gathered in large number is different areas in Cairo in the past few days. They are vowing to defend the Islamist president, who was ousted by the Egyptian army after mass demonstration calling for him to be removed from power.

Mursi was the first freely elected president in Egypt.