France and Germany are seeking talks with the US after a leaked NSA document suggested America has been spying on foreign leaders.
The memo was leaked to the Guardian by ex-NSA analyst Edward Snowden, who has been granted temporary asylum in Russia.
The confidential memo reveals the NSA encouraged senior officials in the White House, State and Pentagon to share their contacts for foreign government figures so the spying agency could add the numbers to their surveillance programmes.
One unnamed US official handed over 200 numbers, including those of 35 world leaders, which were immediately tasked for monitoring, the Guardian reported.
German Chancellor Angela Merkel said the reports have sown seeds of mistrust which could make co-operation on intelligence more difficult, as the row overshadows an EU summit in Brussels.
She added that Germany and France want to "create a framework" with the US on surveillance and want action, not just apologies.
"It’s become clear that for the future, something must change – and significantly," Merkel said at a news conference.
"We will put all efforts into forging a joint understanding by the end of the year for the co-operation of the agencies between Germany and the US, and France and the US, to create a framework for the co-operation."
EU President Herman van Rompuy said other countries could join this initiative.
White House spokesman Jay Carney said President Barack Obama has spoken with Merkel to assure her her phone was not being tapped now nor would be in future, but the statement left open the question of whether it had been tapped in the past.
Italy publication L’Espresso has reported that the US and UK have been spying on Italian internet and phone traffic.
