The 167-page report looked at ground strikes in the region between April 2019 and March 2020 and concluded that the strategy to take back the city from anti-government forces contravened the laws of war.
The global rights group said that the "unlawful" strikes had killed 224 civilians, wounding a further 561, and displacing over 1.4 million people. Three million people live in the area, including many who fled from other regions.
The report also named 10 senior Syrian and Russian officials, who may be "command responsible" for the war crimes. The list included Syrian President Bashar al-Assad and Russian President Vladimir Putin.
Civilian infrastructure was the target
The report claims that the strategy carried out by the two military forces was aimed at civilian rather than military targets.
"The Syrian-Russian alliance strikes on Idlib’s hospitals, schools, and markets showed callous disregard for civilian life," said Kenneth Roth, executive director of Human Rights Watch.
"The repeated unlawful attacks appear part of a deliberate military strategy to destroy civilian infrastructure and force out the population, making it easier for the Syrian government to retake control," he added.
HRW interviewed victims and witnesses as well as inspecting satellite images and photographs as part of their investigation. They determined that the strikes damaged 12 healthcare facilities and 10 schools, taking them out of use.
The attacks also damaged at least five markets, four displaced people’s camps, four residential neighborhoods, two commercial areas, and a prison, a church, a stadium, and an NGO office.
The investigation found no evidence of military targets in the vicinity at the time of the strikes, nor did witnesses report any warnings before the attacks began.
No 'impunity' for war crimes
Ayman Assad, a resident of Idlib city, told HRW that people "are terrified. I don’t feel safe at my place of work, and at the same time, I am constantly worried about my family, especially my two children who are going to school every day. Schools, markets, homes, hospitals, everything is a target. They are targeting life in Idlib"
"It's really only by following up and ensuring that these people who have overseen these war crimes, do not get away with impunity, that there are consequences for pursuing this war crime strategy," Roth said.