The U.S. State Department says U.S. officials have concluded that the U.S. Embassy in Yemen was targeted by three mortar rounds that crashed into a nearby high school and killed a Yemeni security guard.

The attack happened early Wednesday, and at the time U.S. officials said they could not say for certain whether the real target was the U.S. Embassy.

Later Wednesday in Washington, the State Department said U.S. Embassy officials in Yemen have now concluded that the attack was "directed against our embassy." U.S. officials refused to comment further because the incident was under investigation.

In Yemen, the Interior Ministry said the shells fired by unidentified attackers in the downtown Sawan district San'a, the capital, and also wounded five soldiers and 13 schoolgirls.