BRUSSELS (AP) -- European leaders united in anger as they attended a summit overshadowed by reports of widespread U.S. spying on its allies -- allegations German Chancellor Angela Merkel said had shattered trust in the Obama administration and undermined the crucial trans-Atlantic relationship.
The latest revelations that the U.S. National Security Agency swept up more than 70 million phone records in France and may have tapped Merkel's own cellphone brought denunciations from the French and German governments.
Merkel's unusually stern remarks Thursday as she arrived at the European Union gathering indicated she wasn't placated by a phone conversation she had Wednesday with President Barack Obama, or his personal assurances that the U.S. is not listening in on her calls now.
"We need trust among allies and partners," Merkel told reporters in Brussels. "Such trust now has to be built anew. This is what we have to think about."
"The United States of America and Europe face common challenges. We are allies," the German leader said. "But such an alliance can only be built on trust. That's why I repeat again: spying among friends, that cannot be."
The White House may soon face other irked heads of state and government. The British newspaper The Guardian said Thursday it obtained a confidential memo suggesting the NSA was able to monitor 35 world leaders' communications in 2006. The memo said the NSA encouraged senior officials at the White House, Pentagon and other agencies to share their contacts so the spy agency could add foreign leaders' phone numbers to its surveillance systems, the report said.
The Guardian did not identify who reportedly was eavesdropped on, but said the memo termed the payoff very meager: "Little reportable intelligence" was obtained, it said.
Other European leaders arriving for the 28-nation meeting echoed Merkel's displeasure. Swedish Prime Minister Fredrik Reinfeldt called it "completely unacceptable" for a country to eavesdrop on an allied leader.
If reports that Merkel's cellphone had been tapped are true, "it is exceptionally serious," Dutch Prime Minister Mark Rutte told national broadcaster NOS.
"We want the truth," Italian Premier Enrico Letta told reporters. "It is not in the least bit conceivable that activity of this type could be acceptable."
Echoing Merkel, Austria's foreign minister, Michael Spindelegger, said, "We need to re-establish with the U.S. a relationship of trust, which has certainly suffered from this."
France, which also vocally objected to allies spying on each other, asked that the issue of reinforcing Europeans' privacy in the digital age be added to the agenda of the two-day summit. Before official proceedings got under way, Merkel held a brief one-on-one with French President Francois Hollande, and discussed the spying controversy.
After summit talks that lasted until after 1 a.m. Friday, Herman Van Rompuy, European Council president, announced at a news conference that France and Germany were seeking bilateral talks with the United States to resolve the dispute over electronic spying by "secret services" by the end of this year.
"What is at stake is preserving our relations with the United States," Hollande told reporters at his own early-morning news conference. "They should not be changed because of what has happened. But trust has to be restored and reinforced."
"It's become clear that for the future, something must change -- and significantly," Merkel said. "We will put all efforts into forging a joint understanding by the end of the year for the cooperation of the (intelligence) agencies between Germany and the U.S., and France and the U.S., to create a framework for the cooperation."
The Europeans' statements and actions indicated that they hadn't been satisfied with assurances from Washington. On Wednesday, White House spokesman Jay Carney said Obama personally assured Merkel that her phone is not being listened to now and won't be in the future.
"I think we are all outraged, across party lines," Wolfgang Bosbach, a prominent German lawmaker from Merkel's party, told Deutschlandfunk radio. "And that also goes for the response that the chancellor's cellphone is not being monitored -- because this sentence says nothing about whether the chancellor was monitored in the past."
"This cannot be justified from any point of view by the fight against international terrorism or by averting danger," Bosbach said.
Asked Thursday whether the Americans had monitored Merkel's previous communications, White House spokesman Carney wouldn't rule it out.
"We are not going to comment publicly on every specified alleged intelligence activity," he said.
But while the White House was staying publicly mum, Carney said the Obama administration was discussing Germany's concerns "through diplomatic channels at the highest level," as it was with other U.S. allies worried about the alleged spying.