BRUSSELS (AP) — The European Union is introducing new rules to help prevent minerals being used to finance armed conflicts.

The rules passed Monday will oblige the 28 EU member countries to identify the source of their imports of tin, tantalum, tungsten and gold. They must also ensure that their supply chains do not contribute to funding armed conflict.

The four metals are used to make products like mobile phones, cars or jewelry, but armed groups often used forced labor to mine them and use the profits from the sales to fund wars, insurgencies or criminal enterprises.

The EU is encouraging member countries to introduce the rules quickly. They will become binding in January 2021.