German Chancellor Angela Merkel said on Friday said remain over surveillance even as US President Barack Obama pledged to have 'cyber-dialogue' on the issue to address gaps between the two countries over data monitoring and intelligence gathering.

"We have a few difficulties yet to overcome," Merkel said in a joint news conference with Obama at the White House.

Obama also said the United States does not have a blanket "no spy" agreement with any country and that it is not accurate to say the United States offered and withdrew a "no spy" agreement with Germany.

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