WASHINGTON - The United States on Monday pledged to work with Germany over an emerging spy row that threatens to further damage bilateral ties.

White House spokesman Josh Earnest refused to comment on reports about a German national arrested last week over his alleged spying for the US, citing an ongoing investigation in Germany and the matter's link to intelligence.

"We're going to work with the Germans to resolve this situation appropriately," he told reporters at a daily news briefing, calling the relationship with Germany "incredibly important."

"This is a very close partnership that we have on a range of security issues, including some intelligence issues," he said. " That partnership is built on respect, and it's built on decades of cooperation and shared values."

The 31-year-old German, an employee of Germany's foreign intelligence service known as BND, has confessed passing information to a US intelligence agency about Berlin's inquiry into the spying activities of US National Security Agency (NSA), press reports said.

The NSA's spying on German Chancellor Angela Merkel's cellphone, as disclosed by the agency's former contractor Edward Snowden, has strained relations with Berlin with Merkel describing the move as a "breach of trust."

During her visit to Beijing on Monday, the chancellor said it would be "a clear contradiction" of trust between the allies if the new allegations turned out true.

State Department spokeswoman Jennifer Psaki said US Ambassador John Emerson, who was summoned by the German Foreign Ministry over the matter, met with the NSA on Friday.

"Our dialogue will continue on this and every other issue we work together on, but I'm not gonna outline that publicly," she said at a daily press briefing.