Baghdad, Iraq (CNN) -- Two mortar rounds landed inside the Iraqi capital's heavily fortified Green Zone Sunday morning, police said.
It was not known whether anyone was injured or killed in the attack.
The Green Zone houses Iraqi government offices and the U.S. and British embassies.
Similar incidents have occurred in recent months inside the protected area, formerly known as the International Zone. Three mortar rounds struck inside the zone during a July 4 visit by U.S. Vice President Joe Biden.
Also Sunday morning, gunmen killed an employee of Iraq's integrity commission while he was driving his car in western Baghdad, police officials said. And three civilians were wounded when a roadside bomb exploded in eastern Baghdad.
