Two Katyusha rockets were fired at the heavily fortified Green Zone in central Baghdad, the Iraqi military said Thursday.

The incident took place in the early hours of the day when unknown militants fired the rockets at the zone, which houses Iraqi government offices and the US embassy, the media office of the Iraqi Joint Operations Command said in a brief statement.

The two rockets came following several rocket attacks targeted at military bases housing international coalition forces, including one that hit the Camp Taji in northern Baghdad on March 11, killing two US soldiers and one British service member

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The rockets landed near the headquarters of Baghdad Operations Command in the zone, the statement said without giving details about casualties.

The rockets were fired from the al-Nahdha area in downtown Baghdad, on the eastern side of the Tigris River which bisects the Iraqi capital.

Officially called the International Zone of Baghdad, the Green Zone has been frequently targeted by insurgent mortar and rocket attacks. The roughly 10-square-km zone is located on the west bank of the Tigris River.

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The two rockets came following several rocket attacks targeted at military bases housing international coalition forces, including one that hit the Camp Taji in northern Baghdad on March 11, killing two US soldiers and one British service member.

Over 5,000 US troops have been deployed in Iraq to support Iraqi forces in battles against the Islamic State, mainly for training and advisory purposes.