The U.S. government reportedly is ordering some drone strikes based on the location of terror suspects' cell phones -- without necessarily confirming the location of the suspects themselves -- raising concerns about missiles hitting unintended targets.

The details were included in a report published Monday by journalist Glenn Greenwald's newest venture, The Intercept. Though it previously has been reported that National Security Agency data-tracking is used in locating and targeting terror suspects, the Intercept article raised new questions about the accuracy of that data.

The report, citing an unnamed former drone operator and other sources, said the NSA uses a "complex analysis of electronic surveillance" to pinpoint drone strike targets. However, the report said, the CIA and U.S. military don't always confirm who the target is with informants on the ground. This raises the concern that the flagged phone could be in the hands of someone else -- a friend, a family member, someone who's holding the wrong phone at the wrong time -- when the missile is fired.

"It's really like we're targeting a cell phone," the former drone operator was quoted as saying. "We're not going after people -- we're going after their phones."

The Intercept report also detailed how some Taliban leaders have caught onto the NSA's methods, and have tried to evade tracking by purchasing multiple SIM cards and mixing them up.

A spokeswoman with the National Security Council defended the administration's approach to these strikes, without going into fine detail.

"For obvious reasons we can't discuss the specific sources and methods we use to establish near certainty, but our assessments are not based on a single piece of information," spokeswoman Caitlin Hayden told Fox News. "We gather and scrutinize information from a variety of sources and methods before we draw conclusions."

She said officials take "extraordinary care" to make sure counterterrorism actions are within the law and, "before we take any counterterrorism strike outside areas of active hostilities, there must be near-certainty that no civilians will be killed or injured -- the highest standard we can set."

According to the Intercept article, the same spokeswoman declined to say on the record whether strikes are ordered without the use of human intelligence.

The CIA and NSA declined to comment on the report.

Greenwald was among the first journalists to report last year on NSA documents provided by leaker Edward Snowden.

The latest report comes as the Obama administration claims to be tightening its standards for conducting drone strikes -- particularly when an American is the terror suspect.

In one example of these apparent deliberations, the Associated Press reported that officials are wrestling with whether to approve a drone strike against an Al Qaeda-tied U.S. citizen.

While the administration is not commenting publicly on the report, senior U.S. officials acknowledged that the individual is one of several Americans overseas whom the U.S. government is watching closely. They acknowledged that any targeted killing now requires "additional layers of review."

One official described the individual in question as one of the "al-Awlaki's" of the world -- a reference to Anwar al-Awlaki, an American citizen killed in a 2011 drone strike in Yemen.

In a speech last May at the National Defense University, President Obama outlined a more constricted drone policy overseas which, among other changes, made it more difficult to use drones to kill U.S. citizens overseas.

Any such strike, like other drone attacks, would have to be approved by the president.

Asked about the reports at Monday's daily press briefing, White House Press Secretary Jay Carney declined to comment on the specific case. But he said the administration has set a "high threshold" for taking lethal action against any target.