Dozens of protesters gathered at a key Cairo square on Saturday to denounce an Egyptian court's decision to drop a murder charge against ousted president Hosni Mubarak.

The court also acquitted Mubarak's seven security commanders over the deaths of some of the roughly 800 people killed during a revolt that unseated Mubarak in early 2011.

Protesters gathered at an entrance to Cairo's Tahrir Square, the hub of the anti-Mubarak revolt, chanting: "The people demand the toppling of the regime."

The square was closed off by the military, which had deployed on Friday in anticipation of Islamist opposition marches.

Saturday's verdict was met by celebration by Mubarak's supporters, who say his three-decade rule was prosperous and stable.

His ouster was followed by almost four years of tumult which saw the army overthrow his Islamist successor Mohamed Morsi last year following mass protests.

Several of the leading activists who spearheaded the anti-Mubarak uprising have since been