CAIRO, Nov 19 (Aswat Masriya) - Police forces arrested 48 protesters who took to the streets on Wednesday to commemorate the third anniversary of Mohamed Mahmoud clashes, and transferred them to the Abdeen and Qasr al-Nil police stations in Downtown Cairo, a security source told Aswat Masriya.

Human rights lawyer Mahienour El Massry, and three others, were also arrested in Alexandria and sent to Raml police station, according to the "Free Mahienour" Facebook page. The page did not provide further details.

Security forces cordoned Talaat Harb Square with armoured vehicles, eye-witnesses said. Police fired warning shots and dispersed protests around the square, a security source, who preferred to remain anonymous, told Aswat Masriya.

Protesters arrested belong to youth political movements including the April 6 Youth Movement and the Revolutionary Socialists, the source added.

Massry was released on September 21 following her lawyer's appeal against a six-month sentence she was given for violating the protest law. She was arrested in May.

The Mohamed Mahmoud clashes erupted on November 19, 2011, stretching for five days. The clashes between security forces and protesters opposing the then-ruling Supreme Council of the Armed Forces (SCAF) were the deadliest since the January 2011 uprising which toppled President Hosni Mubarak. The clashes left almost 50 killed.