German Chancellor Angela Merkel acknowledged Friday that the United States and Germany have differences to overcome on surveillance, with tensions remaining from the revelation that her personal communications were monitored by the National Security Agency.

“There are differences of opinion on what sort of balance to strike between the intensity of surveillance, of trying to protect the citizens against threats and on the other hand protecting individual privacy and individual freedom and rights of [people] and that will require further discussion between our two countries in order to overcome these differences of opinion,” Merkel said during a joint press conference with President Obama from the Rose Garden.

The German leader was furious with the White House after learning from disclosures by former government contractor Edward Snowden that the NSA had been spying on her cell phone conversations.

And there have been reports detailing quiet negotiations between German and U.S. leaders about a potential “no-spy” agreement between the two nations — but no deal has materialized.

For his part, Obama said the U.S. does not engage in such deals with foreign nations.

“I think what is accurate to say is, is that we do not have a blanket no-spy agreement with any country, with any of our closest partners,” Obama insisted.

The president expressed regret over how the NSA revelations affected the U.S.-German relationship.

“It has pained me,” Obama said, “to see the degree to which the Snowden disclosures have created strains in the relationship.”