The United Nations Environment Program says that environmental crime is helping to finance criminal, militia and terrorists groups.

A new report released Tuesday said that the terror group al-Shabab makes between $38 million and $56 million per year in illegal charcoal. Other groups make between $4 million and $12 million a year by trafficking elephant ivory. And the most lucrative environmental crime is illegal logging, which the report said is worth between $30 billion and $100 billion annually.

Achim Steiner, the head of UNEP, called the report a "sad story" that threatens communities and economies. He said a more systematic and systemic response is needed because of the transnational nature of the threat.

The report was released during the first ever United Nations Environmental Assembly, a weeklong conference in Kenya.