All parties to the six-year-long war in Yemen are violating international law, and the countries supplying them with weapons are helping perpetuate the conflict, UN investigators said in a new report Wednesday.

For the third year in a row, a panel of UN-appointed experts found that all parties to the conflict — the government of Yemen, the Iran-aligned Houthis, the Emirati-backed Southern Transitional Council and the Saudi Arabia-led military coalition — have committed a range of human rights violations.

“Yemen remains a tortured land, with its people ravaged in ways that should shock the conscience of humanity,” said Kamel Jendoubi, the panel’s chairman.

The war between the Houthis, who overran the capital in 2014, and a coalition of Arab nations, which intervened the next year to oust the rebels and restore the internationally recognized government, has created what the UN describes as the world’s worst humanitarian crisis. Thousands of civilians have died, mainly in coalition airstrikes, and the fighting has left roughly 80% of the population in need of some form of aid.