At least three people have reportedly been shot dead and 69 injured after Egyptian troops opened fire in a stand-off with demonstrators, according to media reports.

Violence erupted as supporters of ousted President Mohammed Morsi marched on the Cairo headquarters of the Republican Guard, chanting "down with military rule," according to Sky News.

Sky Middle East correspondent Sam Kiley, who is in Cairo, said shotguns had been used on the ground. He saw several people injured and said live rounds had "certainly" been used.

The army, which removed Morsi on Wednesday after days of unrest, denied shooting live rounds at demonstrators.

However, the BBC's Jeremy Bowen at the scene said he saw soldiers fire on protesters on Friday. According to Bowen, about 2,000 people had marched on the officers' club of the Republican Guard after passionate Friday Prayers at the nearby Rabaa al-Adawiya Mosque. As the crowd grew, got angrier and pushed forward, the troops opened fire -- first into the air, then at the crowd.

Muslim Brotherhood Supreme Leader Mohammed Badie addressed pro-Morsi supporters at a rally in Nasr City, Cairo. "We shall stay in the squares until we bring President Morsi back to power," he told a cheering crowd, according to the Guardian.

The speech came as a surprise as it was reported on Thursday that Badie had been arrested. “I did not escape arrest warrant; such accusations are mere lies,” Badie said. “No one speaks on behalf of the Egyptian people. Everyone has one voice and had the chance to vote.”

He said Morsi is the only president in Egypt. “We will sacrifice ourselves, our souls and our blood for President Morsi,” he added.

Turkish Prime Minister Recep Tayyip Erdogan condemned the removal of Morsi in televised remarks on Friday. "Those who rely on the guns in their hands, those who rely on the power of the media cannot build democracy. ... Democracy can only be built at ballot box," Erdogan said, according to AFP.

Erdogan also criticized the West for refusing to call the ousting a coup. "The West has failed the sincerity test," Erdogan said. "No offense, but democracy does not accept double standards.”