WASHINGTON (AP) — German Chancellor Angela Merkel complained to President Barack Obama in a phone call this week after receiving information that her cellphone may have been monitored by U.S. intelligence agencies. The White House said the U.S. isn't monitoring and won't monitor Merkel's communications — but didn't address what might have happened in the past.

A look at some of the questions swirling around overseas surveillance by the National Security Agency, which has angered allies on two continents and caused concern domestically over the scope of the intelligence-gathering:

___

Q: The NSA spy programs that former analyst Edward Snowden revealed were focused on finding and stopping terrorists, but what other kinds of NSA espionage has he revealed?

A: Snowden also revealed the other types of spying the agency is authorized to do, such as allegedly intercepting foreign diplomats' or leaders' communications, like the alleged eavesdropping on Merkel, as well as on Brazilian President Dilma Rousseff and former Mexican President Felipe Calderon. Other revelations included charts that described how the U.S. supposedly listens in on European Union and United Nations missions, and also spies on citizens in Hong Kong and China.

Snowden's cascade of leaks initially concentrated on how the agency scoops up millions of U.S. phone records and Internet communication data. That is authorized by the 1978 Foreign Intelligence Surveillance Act, which allows a secret court to authorize U.S. electronic surveillance of people engaged in espionage or international terrorism against the U.S. on behalf of a foreign power.

___

Q: Why bug the phone of an ally?

A: Even a close ally like Merkel doesn't share everything with the Americans, but decisions she makes can have a major impact on U.S. foreign, defense and economic policy overseas. Merkel's center-right Christian Democratic party just won an election, and she is in the process of wooing other German political parties to form a coalition government. The party she chooses could pull her political policies in a different direction, in terms of counterterrorism cooperation with the U.S., for instance, or perhaps the new coalition might chill Merkel's support of the NATO mission in Afghanistan.

Story continues

___

Q: The Patriot Act, passed in the immediate aftermath of 9/11, gives the NSA authority to sweep up phone records and Internet communication data. Under what authority could the NSA spy on a world leader's cellphone? Merkel's country has no official involvement in terror, but drives European economic policy. Is the U.S. permitted to spy for many reasons?

A: The NSA's particular marching orders under "Executive Order 12333--United States intelligence activities" include gathering signals intelligence and turning it into something other agencies like the Pentagon and the CIA can use. NSA officers collect that data by any number of means — satellite, spy plane flights or drones all outfitted with still, video and/or infrared cameras, or by placing a microphone in the walls of a foreign embassy, or by using computer technology to hack into a foreign computer terminal, or intercept billions of bites of code as it flows on fiber optic and other cables around the world.

The data an NSA analyst handles can be as varied as the way it's collected. A cryptographer might have to crack the code on an encrypted message, or a language specialist might have to translate a rare dialect.

___

Q: Why would the U.S. want to spy on economic policy?

A: The NSA is also tasked with finding out the kind of policy information that might help U.S. diplomats and trade representatives negotiate future deals, and also what kind of policy changes might be ahead with an economic heavyweight like Germany.

___

Q: Do other countries spy like this on the United States?

A: They do, but most don't have the U.S. technology or financial resources — $10.8 billion for fiscal 2013, according to a budget document Snowden leaked. The NSA is rivaled only by Britain's code-breaking Government Communications Headquarters or GCHQ, an agency the U.S. works with closely, according to the Snowden documents. U.S. ally Israel is considered one of the top counterintelligence threats. U.S. spies and diplomats who work in Israel expect to have phone calls intercepted, and their intelligence work disrupted. Israeli security services are even suspected of breaking into the homes of the successive CIA station chiefs and tampering with sensitive equipment.

___

Associated Press writer Adam Goldman contributed to this report.