Destruction at the UNESCO world heritage site had already been confirmed by the UN's cultural agency a month ago.
The latest, undated video was released on April 3, a day after the IS group lost the city of Tikrit to government and allied forces, its biggest military setback yet in Iraq.
"The Islamic State has sent us to these idols to break them because they are worshipped instead of God," says one of two militants speaking to the camera.
The video shows militants knocking sculptures off the walls of a building, shooting at them with an assault rifle and hacking away at a statue with a pickaxe.
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The destroyed artefacts as seen on the video have metal rebar inside them, leaving it unclear whether they are reconstructed originals or recent replicas.
Hatra is an extremely well-preserved city with a unique mix of eastern and western architecture, located in a desert area about 60 miles (100 kilometres) southwest of the northern jihadist hub of Mosul.
UNESCO has condemned IS' systematic campaign against Iraq's rich heritage as a war crime.
In a tweet posted after the release of the latest video, UNESCO said: "We must stand up against forces that seek to divide Iraq. They attack the humanity we all share.