“The nature and scale of the airstrikes and ground attacks on civilians committed… may amount to crimes against humanity,” the report added.
Attacking civilians is a war crime when it done deliberately or recklessly. When conducted in a widespread or systematic manner, such attacks may amount to crimes against humanity.
Russia has denied targeting civilians, saying it only struck “terrorist targets” in Idlib. However, HRW said Bashar al-Assad, the Syrian president, and Putin were both potentially criminally liable for war crimes as the commanders-in-chief of their forces.
The report named eight other senior Syrian and Russian civilian and military officials who may be culpable under the doctrine of command responsibility.
“Governments should consider unilateral targeted sanctions against those senior officials and commanders credibly implicated in abuses,” HRW said, noting that Russia’s veto at the UN Security Council prevented referrals to the International Criminal Court.
While previous reports have accused Russian and Syrian government forces of targeting civilians, HRW is the first to explicitly argue for command responsibility for the Russian leader.
“This report lays out how intimately involved the Russian military is in Syria’s military operations in Idlib, and that goes all the way up to the Russian commander-in-chief, Vladimir Putin,” said Belkis Wille, the author of the report.
Russia and Syrian military strategy appeared to target civilian infrastructure in order to force the displacement of populations, so that the Syrian army could “simply walk into an area and retake it without there being anyone left there”, Ms Wille added.
In March, the Independent International Commission of Inquiry on Syria published a report implicating Russia in unlawful attacks on civilian infrastructure, saying they likely amounted to war crimes.
Since war broke out in 2011, fighting has killed well over 400,000 people. The UN estimates that nearly 1.4 million were displaced during the Idlib offensive and around 300 towns and villages were depopulated due to attacks by Russian and Syrian government forces.