The Saudi-led coalition that has been bombing Yemen has engaged in "systematic" targeting of civilians in violation of international humanitarian law, while rebel forces in the country have employed African migrants as human shields, United Nations investigators have reported.

The Panel of Experts on Yemen, which was established by the UN Security Council to monitor sanctions on the country, delivered its final report to the council last week. VICE News obtained a copy of the report, which recommended that the council consider forming an international commission of inquiry to investigate human rights abuses in Yemen.

"The coalition's targeting of civilians through air strikes, either by bombing residential neighborhoods or by treating the entire cities of Sa'dah and Maran as military targets, is a grave violation of the principles of distinction, proportionality and precaution," the report says. "In certain cases, the Panel found such violations have been conducted in a widespread and systematic manner."

The panel determined that roughly 60 percent of 2,682 civilian deaths since last March were caused by airstrikes. Among the sites hit by the Saudi-led coalition, according to the report, were "camps for internally displaced people and refugees; civilian gatherings, including weddings; civilian vehicles, including buses; civilian residential areas; medical facilities; schools; mosques; markets, factories and food storage warehouses."

The panel said that it "documented 119 coalition sorties relating to violations of international humanitarian law." In three cases, it documented "civilians fleeing residential bombings and being chased and shot at by helicopters." It found that coalition aircraft attacked hospitals on 22 occasions.

The Saudi-led coalition began operations in Yemen on March 26 after Houthi rebels and allied forces loyal to the country's former President Ali Abdullah Saleh advanced deep into the country's south. The government in Riyadh says that its goal is to reinstate current President Abd Rabbuh Mansour Hadi, who fled the country prior to the start of the bombing campaign. The coalition enjoys logistical and intelligence support from the US military, and has deployed Latin American mercenaries under the guidance of the United Arab Emirates. The use of mercenaries, said investigators, "increases the likelihood of violations of international humanitarian law."

A combination of bombings and ground forces — often made up of local militias that have varying allegiances — have pushed the Houthis back in some areas, including the port city of Aden. The rebels and Saleh's forces still control most of Yemen's populated regions, however.

In reviewing the conflict, investigators also documented a litany of violations against civilian populations that were committed by the Houthis and units loyal to Saleh.

Their combined military has routinely and indiscriminately launched rockets and shells in residential areas. In Aden and Taiz — Yemen's second largest city where more than 200,000 people remain under siege — Houthi-Saleh forces were documented attacking "medical facilities, schools and other civilian infrastructure, and using snipers positioned atop buildings to target people seeking safety, medical care or food."

In Aden, the combined forces were cited for firing at boats carrying civilians, using "poorly aimed surface-to-air missiles," and laying land mines as they retreated from the city in a "grave violation of international humanitarian law."

In one particularly heinous illustration of the gravity of their crimes, the panel cited three UN and international humanitarian workers who claimed that "Houthi-Saleh forces had more than once housed African migrants and refugees as human shields in unused buildings in Aden previously targeted by airstrikes, or where weapons caches were claimed to be stored."

The panel said that both Houthi-Saleh forces and resistance fighters targeted displaced Yemenis and forcibly recruited migrants from the Horn of Africa.

"Armed groups have forcibly recruited [and] trafficked third-country nationals, many of whom are young people or minors sold by trafficking networks," wrote investigators. "Migrants and refugees have accordingly been viewed as fighters or potential fighters, irrespective of their civilian status or vulnerable status as trafficking victims, and come under attack."

The Houthi-Saleh alliance, which the panel described as a "a new hybrid armed group," has been largely financed by seized state assets, taxes on produce like the mild stimulant khat, extortion, and the accumulated wealth of Saleh and his family.

In light of the crimes perpetrated by all sides, the Panel of Experts recommended that the Security Council consider establishing an international commission of inquiry to investigate violations of international law, and identify perpetrators.

Such an international mechanism was proposed in September of last year by UN High Commissioner for Human Rights Zeid Ra'ad al Hussein. That month, the Netherlands floated a resolution at the Human Rights Council in Geneva to create a human rights mission in the country. Faced with extensive opposition from Saudi Arabia and other Gulf countries — and silence from the US — the Dutch wilted and an Arab text that included no stipulation for international investigators was passed instead.