The United States should cut off its massive military aid to Egypt if further violence targets anti government protesters in Cairo, Human Rights Watch said on Wednesday after deadly clashes.
Washington, which has called for restraint in the wake of anti government protests for over a week, deplored the violence against "peaceful protesters" while UN chief Ban Ki moon said attacks on demonstrators were "unacceptable."
At least three people were killed and hundreds injured, Egyptian sources said.
"Egyptian security forces failed to protect those peacefully assembling in Tahrir Square in Cairo on February 2, 2011, from pro government provocateurs armed with petrol bombs, sticks and whips," the New York based watchdog said in a statement.
"The United States and the European Union should... tell President Hosni Mubarak and Egypt's military commanders that the army's actions on February 2 raised serious doubts about its willingness to protect pro-democracy protesters from violent attacks, and that their failure to uphold fundamental human rights... will prompt an immediate suspension of all military assistance."
Egypt, a critical US ally in an often volatile Middle East region, receives around $1.5 billion in military aid from Washington each year.
From early afternoon until well into the night, regime supporters and opponents threw stones and battled with sticks and fists in Cairo's Tahrir, or Liberation, Square, the epicenter of protests that have rocked the Egyptian regime and sent shockwaves around the Arab world.
Further violence gripped the Egyptian capital in the early hours of Thursday as the uprising entered its 10th day, with witnesses saying at least two people were killed in gunfire aimed at anti regime protesters in Tahrir Square, with many more wounded.
HRW also criticized the Palestinian Authority for violence against demonstrators in Ramallah protesting in sympathy with the Egyptians.
Police beat and detained participants in that demonstration, as well as, at least two journalists and a Human Rights Watch staffer. "The Palestinian Authority should immediately make clear that its 'state building' training of security forces does not include beating peaceful demonstrators," said Sarah Leah Whitson, HRW's Middle East and North Africa director.
"The PA should take action against the responsible police officers or the US and EU should find another use for their taxpayers' money."