Then-Secretary of State Hillary Clinton received emails from her top aides warning about dangerous security conditions in Benghazi, Libya, in the run-up to the terrorist attack that killed a U.S. ambassador and three other Americans there in 2012, documents disclosed on Friday show.

The messages were part of a batch of about 300 emails involving Benghazi that were made public by the State Department. State officials already gave the emails in February to a special House committee that is looking into the Benghazi attacks and...