Brussels: European Union leaders on Friday vowed to maintain a strong trans-Atlantic partnership despite their anger over allegations of widespread US spying on its allies. France and Germany insist new surveillance rules should be agreed with the US by the end of the year.

“What is at stake is preserving our relations with the United States,” French President Francois Hollande said yesterday, insisting that “trust has to be restored and reinforced.”

Heading into the final day of their summit, most EU leaders shared the view that good partnership trumped deep resentment over the snooping of US security services.

“The main thing is that we look to the future. The trans-Atlantic partnership was and is important,” said President Dalia Grybauskaite of Lithuania, whose country holds the EU presidency.

On Thursday’s opening day of the summit, the spying issue united the 28 EU leaders in criticising the snooping on Thursday after allegations surfaced that German Chancellor Angela Merkel had one of her mobile phones tapped by US services.

Her government said yesterday that senior officials will travel to the US “shortly” for talks at the White House and with the National Security Agency to push forward efforts to clear up the surveillance allegations. In addtion, members of the European Parliament’s civil liberties committee will fly to Washington on Monday for the talks and explore “possible legal remedies for EU citizens” resulting from the alleged surveillance, the committee said in a statement on yesterday.

Merkel and Hollande insisted that beyond being fully briefed on what happened in the past, the European allies and Washington need to set up common rules for surveillance which does not impede the fundamental rights of its allies.

“The United States and Europe are partners but this partnership must be built on trust and respect,” Merkel said yesterday. “That of course also includes the work of the respective intelligence services.”

White House spokesman Jay Carney said the Obama administration was discussing Germany’s concerns “through diplomatic channels at the highest level,” as it was with other US allies worried about the alleged spying.

It has emerged that the NSA monitored the phone conversations of 35 world leaders after being given the numbers by an official in another US government department, according to a classified document provided by whistleblower Edward Snowden.

The confidential memo reveals that the NSA encourages senior officials in its “customer” departments, such the White House, State and the Pentagon, to share their “Rolodexes” so the agency can add the phone numbers of leading foreign politicians to their surveillance systems.

The document notes that one unnamed US official handed over 200 numbers, including those of the 35 world leaders, none of whom is named. These were immediately “tasked” for monitoring by the NSA.

Prime Minister David Cameron yesterday accused US whistleblower Edward Snowden and unnamed newspapers of assisting Britain’s enemies by helping them avoid surveillance by its intelligence services.

In his strongest remarks on the subject yet, Cameron told a news conference in Brussels that the classified information which Snowden had leaked was going to make it harder for Britain and other countries to keep its citizens safe from people who wanted to “blow up” families.

“What Snowden is doing and, to an extent, what the newspapers are doing in helping him do what he is doing, is frankly signalling to people who mean to do us harm how to evade and avoid intelligence and surveillance and other techniques,” Cameron told reporters.

Meanwhile, Spanish Prime Minister Mariano Rajoy said yesterday he would call in the US ambassador to Madrid to explain reports of American spying on the country, a close ally of Washington.

“We do not have evidence that Spain has been spied on ... but we are calling in the ambassador to get information,” Rajoy said after an EU summit dominated by the growing scandal over US intelligence activities in supposedly friendly countries.

- Compiled from agencies