The U.N. human rights chief says the Assad regime and its allies have continued a relentless campaign against civilians in northwestern Syria amid a "collective shrug" by the international community to the escalating violence.
A Syrian government military offensive, backed by Russian airpower, began April 30 against the last major rebel stronghold, home to 3 million people. More than 440,000 have been displaced by the violence.
The office of Michelle Bachelet said in the last 10 days alone at least 103 civilians, including 26 children, were killed.
Bachelet said Friday that the world's most powerful nations are failing to lead in dealing with the Syrian crisis "resulting in a tragedy on such a vast scale that we no longer seem to be able to relate to it at all."
Bachelet stressed that medical facilities, schools, markets and other clear civilian targets have been hit.
"These are civilian objects, and it seems highly unlikely, given the persistent pattern of such attacks, that they are all being hit by accident," she said in a statement.
"Intentional attacks against civilians are war crimes, and those who have ordered them or carried them out are criminally responsible for their actions."
Syria's opposition has condemned the bombardment as "genocide", while aid groups have branded the carnage in Idlib the latest "nightmare" in the eight-year conflict.
Bachelet said that even as "airstrikes kill and maim significant numbers of civilians several times a week" the international "response seems to be a collective shrug, with the Security Council paralysed."
"This is a failure of leadership by the world's most powerful nations," the rights chief added.
Top UN officials have repeatedly condemned the Security Council's inaction on Syria, with several measures vetoed Damascus ally Russia.
Syria's war has killed hundreds of thousands of innocent people and displaced millions since it started in 2011 with a brutal crackdown on protests against the Assad regime.
