The United States heard widespread concern Monday over excessive use of force by law-enforcement officials against minorities as it faced the U.N.'s main human rights body for a review of its record.

Washington also faced calls to work toward abolishing the death penalty, push ahead with closing the Guantanamo Bay detention center and ensure effective safeguards against abuses of Internet surveillance. Its appearance before the U.N. Human Rights Council in Geneva is the second review of the U.S. rights record, following the first in 2010.

A string of countries ranging from Malaysia to Mexico pressed the U.S. to redouble efforts to prevent police using excessive force against minorities.

"We must rededicate ourselves to ensuring that our civil-rights laws live up to their promise," Justice Department official James Cadogan told delegates, adding that that is particularly important in the area of police practices and pointing to recent high-profile cases of officers killing unarmed black residents.

"These events challenge us to do better and to work harder for progress through both dialogue and action," he said at the session's opening. He added that the government has the authority to prosecute officials who "wilfully use excessive force," and that criminal charges have been brought against more than 400 law-enforcement officials in the past six years.

Several countries, including Brazil and Kenya, voiced concern over the extent of U.S. surveillance in the light of reports about the National Security Agency's activities.

David Bitkower, a deputy assistant attorney general, responded that "U.S. intelligence collection programs and activities are subject to stringent and multilayered oversight mechanisms." He added that the country doesn't collect intelligence to suppress dissent or to give U.S. businesses a competitive advantage, and that there is "extensive and effective oversight to prevent abuse."

Faced with widespread calls for a moratorium on executions and a move to scrap the death penalty, Bitkower noted that it is an issue of "extensive debate and controversy" within the U.S. He pointed to "heightened procedural safeguards" for defendants prosecuted for capital offenses.

Brig. Gen. Richard Gross, the legal counsel to the chairman of the U.S. joint chiefs of staff, told the council that President Barack Obama has said closing Guantanamo -- in which he has been thwarted by Congress -- is "a national imperative." The remaining detainees are detained lawfully, he said.

The so-called Universal Periodic Reviews of U.N. member nations' human rights records started in 2008. Each country's record is reviewed roughly every four years.