The same day that Vice President Joe Biden paid a surprise visit, the highly fortified International Zone in Baghdad came under fire.

US Ambassador Christopher Hill said that at least one round seems to have landed in the embassy grounds Tuesday. Biden was not injured.

The embassy and many government buildings are located in the zone.

Warning alarms were sounded, and security was stepped up in the International Zone, which is informally known as the Green Zone.

It is not clear what weapons were fired or if Biden was near the location where the rounds hit. For security reasons, reporters traveling with the vice president are not allowed to report his location.

(via CNN)