CAIRO: The United States expressed concern Tuesday about growing political polarization in its major ally Egypt and a “climate of impunity” over abuses by police and security forces in the most populous Arab nation.

At a news conference after a four-day visit, U.S. Assistant Secretary of State for Human Rights, Democracy and Labor Michael Posner avoided direct criticism of the Muslim Brotherhood-led government of President Mohammad Mursi.

But he said young people’s economic and political concerns, which had led to recent violent protests, should be addressed, and the government should “reach out widely” to other political and social forces and hold consultations on concerns about the Islamist-tinged constitution it pushed through in December.

“While recognizing the need for the Egyptian government to take specific steps to build confidence and to address valid concerns, we condemn this violence unequivocally,” Posner said.

Noting that the authorities had the right and duty to ensure public order and stop violence by protesters, he said: “At the same time there are credible reports that police and security forces have used excessive force.

“We have heard reports of cases throughout Egypt where the police have resorted to torture and other forms of cruel treatment of those in their custody. There are also reports of deaths in custody,” he said.

Some abuses were under investigation but there had been few successful prosecutions so far.

“This contributes to a climate of impunity and a lack of meaningful accountability for these actions,” Posner said, adding that authorities had also failed to identify and punish perpetrators of “an alarming number of rapes and other acts of violence against women.”

Asked whether human rights were better or worse in Egypt than under former President Hosni Mubarak, toppled in a popular uprising two years ago, he declined to make a comparison but said young people’s expectations were higher now.

His comments came as hundreds of Egypt’s low-ranking policemen staged protests demanding they not be used as a tool for political oppression in the country’s ongoing turmoil.

Dozens of policemen rallied outside local security administration headquarters in at least 10 provinces. Some of them carried signs reading, “we are innocent of the blood of the martyrs.”

Although small, the protests marked a rare instance of dissent by Egypt’s police force. The rallies reflect fears among many policemen of a public backlash after weeks of violent crackdowns on anti-government protests.

Rights activists allege that police have used excessive force against the latest wave of protests that started on the eve of the second anniversary of the uprising that toppled Mubarak.

In the Mediterranean city of Alexandria, policemen gathered outside security headquarters shouting: “Down with the interior minister.” They also chanted: “No to the Brotherhood takeover of the Interior Ministry,” alleging that the country’s largest Islamist group is packing state institutions with its members.