The FBI is investigating letters sent to newspapers nationwide that say “Goldman Sachs. Hundreds will die. We are inside. You cannot stop us,” the bureau said Friday, but government and company officials are downplaying the threat.

U.S. Postal Inspection Service said the letters were sent to 20 small to mid-size newspapers, including publications in Indiana, Texas, Idaho, Tennessee and New Jersey.

“We take these things very seriously,” said FBI spokesman Bill Carter.

But he added, “We have no specific and credible information about a credible threat to Goldman Sachs other than these letters.”

And Goldman spokesman Lucas Van Praag told CNN an FBI analysis has “concluded the threat is extraordinarily incredible,” meaning the threat lacks credibility. The investment firm has been in close contact with the FBI on the issue since late June, he said.

The threat is unique in terms of specifically targeting Goldman employees, Van Praag added. A year ago, he said, there were threats against a number of U.S. banks.

“We have a broad range of security measures in place to counter all likely threats and we’re monitoring the situation closely,” a written statement from the bank reads.

The FBI does not yet know who mailed the letters, which were signed “A.Q.U.S.A.,” FBI sources told CNN.