The 23-member European Parliament delegation began a series of meetings Monday with U.S. lawmakers and officials in several government agencies, including the National Security Council at the White House. The talks are scheduled to extend through Wednesday.
European officials are protesting to Washington following revelations that a U.S. intelligence program collected data about millions of telephone calls, and monitored calls involving senior leaders.
The U.S. ambassador in Madrid was called in to receive a Spanish government protest Monday, after reports that the National Security Agency collected data on the origin and end point of millions of Spanish telephone calls.
A Spanish government minister reportedly called the operation "inappropriate and unacceptable" conduct by a friendly nation.
The latest revelation is reportedly from information provided by fugitive former NSA contractor Edward Snowden, who has received temporary asylum in Russia. His information also led to reports of NSA tracking of millions of French phone calls.
U.S. policy expert James Boys at London's King’s College said the alleged surveillance makes clear how seriously American officials view their responsibility to do everything possible to fight terrorism.
"What this incident does demonstrate is that there are continuing U.S. national security interests that will be continued irrespective of who is in the White House, and that they will be pursued irrespective of the potential hurt to feelings that may be caused, even in allies and capitals around Europe," said Boys.
Massive call tracking operations identify the origin and end-point of phone calls in an effort to establish patterns and find terrorists, without actually listening to the calls.
The latest reports of such tracking come just days after allegations -- again based on information from Snowden -- that U.S. intelligence officials did listen to phone calls by as many as 35 world leaders over many years.
Among them were German Chancellor Angela Merkel, who dispatched senior intelligence officials to Washington to demand an investigation.
German media report U.S. President Barack Obama knew about the surveillance. The NSA denies it, though, and the Wall Street Journal newspaper reports the president was not aware of the program until a few months ago, and he ordered it stopped.
Berlin-based Journal reporter Anton Troianovski said whether the president knew or not, this is becoming "a major event" in U.S.-German relations.
"It's really something that's being taken personally by much of the political leadership here. Chancellor Merkel has spoken over and over in the last few days about a relationship of trust being broken, and the need to reestablish trust. People really struggle to explain what the point of this would be."
Troianovski said the long-term impact of the revelations will depend on how well the United States explains its actions to European leaders and their people.
At a summit last week, European leaders took turns criticizing the U.S. intelligence gathering program. Boys is suspicious, though, of the European outrage.
"The European intelligence services are allied with the National Security Agency. And European powers will benefit from some of the intelligence that's gathered by the National Security Agency. So, sure -- there are some ruffled feathers, but all European leaders will be aware that conversations are monitored. So I think there's a lot of public posturing going on here," said Boys.
A senior member of the U.S. Congress expressed a similar view on Sunday. Mike Rogers, the Republican chairman of the House of Representatives Intelligence Committee, called the European objections "disingenuous," and said the call tracking helps keep the United States and its allies safe.
The New York Times newspaper reports that France and Germany will try to address the issue through even closer ties with U.S. intelligence, in an arrangement that would share the most sensitive information in exchange for a promise not to spy on each other. The Times said European governments also may require global communications firms to get their approval before providing U.S. intelligence agencies with information about calls or emails in their countries.