Egypt’s prosecutor-general Hisham Barakat ordered on Tuesday the detention of 22 supporters of deposed president Mohamed Morsi for allegedly instigating attacks on anti-Morsi protesters in Tahrir Square on Monday.

The defendants are facing charges of attempted murder of the anti-Morsi protesters, who were holding a sit-in in Tahrir Square, reported state news agency MENA. They will be held in police custody for 15 days pending investigations.

The defendants are also accused of possessing firearms and unlicensed weapons.

Clashes broke out on Monday when Morsi supporters en route to the US embassy attacked anti-Morsi protesters in nearby Tahrir Square. Rocks were thrown and gunshots fired, although there were differing reports from the scene about how the clashes started. One person died and at least 23 were injured during the violence.

According to prosecutors, initial investigations reveal that pro-Morsi protesters initiated the attack on Tahrir Square using stones, live ammunition and birdshot.

Investigations also reveal that one of the 22 defendants was shown firing a gun in a video of the clashes that has since been widely spread online. According to the prosecution, a defendant has admitted that he is the person shown in the video, and also said that he came to Tahrir from the pro-Morsi sit in at Rabaa Al-Adawiya Mosque in Nasr City.

Further investigations are ongoing.

At least 12 people were killed on Monday and in the early hours of Tuesday in clashes between supporters and opponents of Morsi across Cairo and Giza and in the neighbouring governorate of Qalioubiya.

Morsi was overthrown on 3 July as part of the armed forces’ roadmap for Egypt’s future, which was enforced following mass nationwide protests against the former elected president.

Thousands of Morsi’s supporters have since been staging a sit-in at Rabaa Al-Adawiya in Cairo's Nasr City until he is restored to office.