Democratic Senator Chris Murphy and two members of the House of Representatives will visit Berlin on Monday and Brussels Tuesday to address the transatlantic partnership as well as concerns about National Security Agency surveillance activities.
In Berlin, they are scheduled to meet with German Foreign Minister Guido Westerwelle Monday around noon, as well as members of the Bundestag lower house.
German news magazine Der Spiegel reported that Merkel and President Joachim Gauck had "rebuffed" requests for a meeting with the US delegation.
Murphy, who chairs the Senate Foreign Relations Subcommittee on European Affairs, told AFP that the trip was an opportunity to tell the Europeans, and the Germans in particular, that "many of the concerns that they raised are not unfamiliar to those of us in the United States Congress."
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"We're having a conversation in this country about the intrusion of US intelligence into the lives of American citizens and it's appropriate for us to also have a conversation about how that affects Europeans," he added.
The visit comes after Merkel called for answers Monday over "grave" US spying accusations testing transatlantic ties, including fledgling trade talks.
A poll showed earlier this month that Germans' trust in the United States took a battering in the wake of the spy revelations, with 61 per cent saying Washington could not be trusted.
With memories of the methods employed by the Nazis and East Germany's communist regime still very much alive, Germans are especially sensitive to the issue of state surveillance.