FORT MEADE, Md. – A career U.S. diplomat testified Thursday that Army Pfc. Bradley Manning's unauthorized release of classified material horrified the State Department and jeopardized relationships with U.S. allies overseas.

Elizabeth Dibble, principal deputy U.S. assistant secretary for Near Eastern Affairs who next week becomes deputy chief of mission in London, testified about the damage inflicted when Manning gave the anti-secrecy organization WikiLeaks highly classified data in 2010.

Dibble said there was instant "horror and disbelief" at the State Department headquarters "that our diplomatic communications had been released and were available on public websites for the world to see."

U.S. embassies abroad are the "eyes and ears of the U.S. on the ground there," she said, and internal working papers from Washington or inside the embassies should never be shared with other countries — especially as the U.S. attempts to shape its foreign policy.

If there is no confidentiality, she said, a foreign official or country may be "burned."

Under cross-examination by defense attorneys, Dibble was asked about a statement from former Secretary of Defense Robert Gates that government secrets often "leak like a sieve." She said that was not true. "It makes a good sound bite," she said, "but I don't agree with it."

A second senior diplomat, John Feeley, testified that he was based in Mexico City in 2010 when he first learned that the Manning leaks included numerous confidential State Department cables.

Now the principal deputy assistant secretary for the Western Hemisphere, he said there was an "impact" from the leaks. He discussed that later in a closed classified session. Dibble also gave additional testimony in a closed session.

In a statement from London, WikiLeaks founder Julian Assange defended Manning, calling him "the quintessential whistleblower."