France and Germany pushed Friday for Washington to agree rules for the spy game after damaging revelations the United States tapped German Chancellor Angela Merkel's mobile phone, the European Union said.

Leaders "took note of the intention of France and Germany to seek bilateral talks with the US", EU President Herman Van Rompuy told a press conference after a first day of summit talks wrapped up.

Van Rompuy said other countries could join Berlin and Paris should they wish in seeking this trust-based "understanding" with the United States "before the end of the year" in the field of intelligence gathering.

In a statement in the early hours, the leaders of the 28-state EU "underlined the close relationship between Europe and the USA and the value of that partnership".

They "expressed their conviction that the partnership must be based on respect and trust, including as concerns the work and cooperation of secret services".

Britain has long-established intelligence ties with the United States but questioned on London's role, Van Rompuy stressed that all leaders had agreed on the text.

Britain "of course has a special relationship (with the United States) … but they are completely on board with this text", he added.

Prime Minister David Cameron made no comment to waiting reporters neither on his way in nor on leaving the meeting.

Merkel had arrived at the two-day talks saying: "Spying between friends, that's just not done" after reports the US National Security Agency had eavesdropped her calls.

"We need trust between partners and such trust needs to be re-established," she said.