The State Department acknowledged for the first time Friday that “top secret” information has been found in emails that passed through the private email server Hillary Clinton used while leading the agency, elevating the issue in the presidential campaign three days before the hotly contested Iowa caucuses.

The information was contained in 22 emails, across seven email chains, that were sent or received by Clinton, according to a State Department spokesman. The emails will not be disclosed as part of an ongoing  release of Clinton’s email correspondence from her years as secretary of state, even in highly redacted form.