German Chancellor Angela Merkel's government Monday announced a probe into ties between its secret services and U.S. agencies whose sweeping online surveillance was revealed by fugitive intelligence analyst Edward Snowden.

It reacted to a report by news weekly Der Spiegel which said documents provided by Snowden showed that German services closely cooperated with the U.S. National Security Agency (NSA) and used its Internet spy software XKeyscore.

U.S. Treasury Secretary Jack Lew praised the "hard work" of Greece's prime minister Antonis Samaras on Sunday and urged his government to continue with economic reform.

Lew publicly declared his confidence in the conservative administration of Samaras following a meeting in Athens.

German Chancellor Angela Merkel has come out strongly in favor of an international agreement to protect electronic data, following revelations by fugitive former intelligence analyst Edward Snowden about U.S. surveillance program PRISM.

"We should be able, in the 21st century, to sign global agreements," Merkel told the weekly Welt am Sonntag, in an interview to be published Sunday.

Nine weeks before elections, German Chancellor Angela Merkel weathered a media grilling Friday on U.S. online surveillance and her government's role in it, insisting she was still waiting for answers from Washington.

Merkel remains the frontrunner for the September 22 vote, and a new poll suggests the snooping affair is not yet a major election issue -- but the opposition hopes this will change while the media is turning increasingly hostile.

The EU's justice commissioner hailed Monday a call by German Chancellor Angela Merkel for tighter privacy curbs on Internet giants led by Google, amid reports of sweeping U.S. government surveillance online.

Viviane Reding urged the leaders of the European Union's 27 other member states "to follow Chancellor Merkel's leadership in data protection" and ensure a law revamp proposed 18 months ago is finalized before European Parliament elections in May.

Moscow wants to exchange a married couple of Russian spies jailed this month in Germany for at least one convict jailed in Russia on charges of spying for the West, a report said Monday.

Russia's Kommersant newspaper said that the Russian secret services wanted to bring the pair -- known only by their code names Andreas and Heidrun Anschlag -- back home to Russia after decades as "sleepers" in Germany.

German Chancellor Angela Merkel on Sunday called for the release of Egypt's former president Mohammed Morsi, who was arrested on July 3 after being deposed by the army.

She said she agreed with her Foreign Affairs Minister Guido Westerwelle "that Mr. Morsi should be released" and called for "an inclusive (political) process involving all groups of the Egyptian population", speaking with public broadcaster ARD.

Qatar plans to order 118 Leopard tanks from Germany over the next seven years, the Bild am Sonntag newspaper said Sunday, citing sources close to the Qatari government.

The paper said the tanks will be manufactured by Krauss-Maffei Wegmann and Rheinmetall.

Germany on Friday called for the release of ousted Egyptian president Mohammed Morsi amid mounting tensions between supporters and opponents over his overthrow.

"We call for an end to the restrictions on Mr Morsi's whereabouts," a foreign ministry spokesman told reporters.

German Chancellor Angela Merkel on Wednesday defended the role of secret services in keeping populations safe, but also said she only learnt of the U.S.-run PRISM surveillance program through media reports.

In her most detailed comments yet on the snooping and spying claims made by fugitive former U.S. intelligence contractor Edward Snowden, she also stressed that the United States remained "Germany's most faithful ally".