The United Nations has criticized the United States' use of armed drones in an attack that killed the Number 3 commander in the international Al Qaeda terrorist organization.

Philip Alston, the U.N. Special Representative on Extrajudicial Executions, called on the United States to limit its use of the technology outside the direct combat theaters in Afghanistan and Iraq.

Sheikh Said Al-Masri was assassinated by a CIA-operated drone in a tribal area of Pakistan near the border of Afghanistan sometime last week.

Alston issued a 29-page report warning that the growing use of the armed drones by the U.S. would result in “competing drone attacks” by dozens of countries against anyone “labeled as terrorists by one group or another.” According to the U.N. official himself, at least 40 other countries already have drone technology.

An introductory statement that accompanied the report said, “The United States seems oblivious to this fact when it asserts an ever-expanding entitlement for itself to target individuals across the globe. But this strongly-asserted but ill-defined license to kill without accountability is not an entitlement which the United States or other states can have without doing grave damage to the rules designed to protect the right to life and prevent extrajudicial executions.”

The report was submitted to the U.N. Human Rights Council in Geneva, which the U.S. joined after President Barack Obama took office.

Alston acknowledged Wednesday in an interview with The New York Times that the Al Qaeda terrorist was “a very clearly acceptable target.” He went on to wonder “who the other strikes are against, and what efforts are being made to comply with the rules.”

The United States did not respond directly to the report, although a White House spokesman referred reporters to an earlier speech by State Department legal adviser Harold Koh.

“A state that is engagement in an armed conflict or in legitimate self-defense is not required to provide targets with legal process before the state may use lethal force,” Koh said.

But the United Nations has questioned the State Department's definition of what a legitimate target might be, and rejected “pre-emptive self-defense” as a justification for killing terrorism suspects away from the direct combat theater.