Egyptian police used water cannon on Tuesday to disperse the first unauthorized protest staged in Cairo since the adoption of a law that regulates demonstrations

Egyptian police used water cannon on Tuesday to disperse the first unauthorized protest staged in Cairo since the adoption of a law that regulates demonstrations.

Protesters were demanding the prosecution of those responsible for the deaths of demonstrators in November 2011 when opponents of the then military junta clashed with police in the capital.

On Sunday, interim president Adly Mansour passed a law that allows security forces to gradually step up force while dispersing protests.

It allows security forces to first issue verbal warnings to protesters, then use water cannon, tear gas and, finally, birdshot while breaking up demonstrations.

Amnesty International said the law was a "serious setback that poses a grave threat to freedom of assembly and gives security forces a free rein to use excessive force, including lethal, against demonstrators".

Since August 14, Egypt's military-installed authorities are engaged in confrontation with Islamist supporters of ousted president Mohammad Mursi, the country's first democratically elected leader.

He was overthrown on July 3 after mass street protests against his turbulent single year of rule.