UNITED NATIONS -- Iraq's ambassador to the United Nations asked the U.N. Security Council on Tuesday to look at allegations that the Islamic State of Iraq and Syria (ISIS) is using organ harvesting as a way to finance its operations.

Ambassador Mohamed Alhakim told reporters that in the past few weeks, bodies with surgical incisions and missing kidneys or other body parts have been found in shallow mass graves.

"We have bodies. Come and examine them," he said. "It is clear they are missing certain parts."

He also said a dozen doctors have been "executed" in Mosul for refusing to participate in organ harvesting.

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Alhakim briefed the council on the overall situation in Iraq and accused ISIS of "crimes of genocide" in targeting certain ethnic groups.

The outgoing U.N. envoy to Iraq, Nikolay Mladenov, told the council that 790 people were killed in January alone by terrorism and armed conflict.

Mladenov noted the increasing number of reports and allegations that ISIS is using organ harvesting as a financing method, but he said only that "it's very clear that the tactics ISIL is using expand by the day." He used an alternative acronym for the group.

He said Iraq's most pressing goal is to win back the vast territory that ISIS has seized in the past year. The Sunni militants seized a third of both Iraq and neighboring Syria and imposed strict Sharia law.

"Especially worrying is the increasing number of reports of revenge attacks committed particularly against members of the Sunni community in areas liberated from ISIL control," Mladenov said.

Sheikh Ahmed Aburisha is a tribal leader from Anbar province in Iraq, 85 percent of which is under ISIS control. In late January, he visited Washington to urge the U.S. to give his tribes weapons and money so they can defeat ISIS in Anbar.

"Vice President Biden and Gen. [John] Allen have a clear picture of what is happening in Iraq and Anbar and what type of support is needed for the fighters in Anbar," Aburisha told CBS News' Jennifer Janisch. "We have received promises and we hope that these promises will materialize in reality on the ground."