BERLIN – EU leaders meeting in Brussels say distrust of the US over spying could harm the fight against terrorism.
A statement agreed by the leaders says that "a lack of trust could prejudice" intelligence-gathering co-operation.
France and Germany are pushing for talks with the US to find an "understanding" by the year's end.
A number of allegations against US intelligence agents have surfaced this week, including the bugging of German Chancellor Angela Merkel's phone.
In addition there have been claims that the US National Security Agency (NSA) monitored millions of French telephone calls.
On Thursday, the UK's Guardian newspaper also reported that it had obtained a confidential memo from the NSA suggesting it had monitored the phones of 35 world leaders.
The various allegations have overshadowed the EU summit in Brussels.
The statement of heads of state or government, released on Friday, reflects the EU leaders' conclusions following their talks on Thursday.
It says the recent intelligence issues had raised "deep concerns" among European citizens.
The statement says the leaders "underlined the close relationship between Europe and the USA and the value of that partnership".
It continues: "[The leaders] stressed that intelligence-gathering is a vital element in the fight against terrorism."
And it went on: "A lack of trust could prejudice the necessary cooperation in the field of intelligence-gathering."
Talks among the EU leaders continued late into Thursday night.
Speaking afterwards, Mrs Merkel said: "We need trust among allies and partners. Such trust now has to be built anew.
"The United States of America and Europe face common challenges. We are allies. But such an alliance can only be built on trust. That's why I repeat again: spying among friends, that cannot be."
Germany and France said they were proposing talks with the US to settle the row by the end of the year.
The leaders' statement said: "The heads of state or government took note of the intention of France and Germany to seek bilateral talks with the USA with the aim of finding before the end of the year an understanding on mutual relations in that field.
"They noted that other EU countries are welcome to join this initiative."