Gold-rich Sudan discussed boosting cooperation in the mining sector with Russia, as Moscow strengthens ties with the North African nation’s military-led government amid a 17-month civil war.

A meeting between Sudanese mining officials and Russia’s ambassador and representatives of its chamber of commerce in the Red Sea city of Port Sudan touched on ways to expand investment opportunities, Sudan’s minerals ministry said in a statement.

The encounter is the latest sign of Russia’s deepening relations with Sudan’s army, which is battling the rival Rapid Support Forces paramilitary group in a conflict the US estimates may have killed as many as 150,000 people. A Sudanese army official in May suggested his side might get weapons in exchange for letting the Kremlin establish a logistical support center on its coast, although no formal deal has been signed.

Russian-controlled mercenaries from the Wagner Group had previously been accused by the US of delivering surface-to-air missiles to the RSF. Russian support for the RSF was likely to protect the country’s interests in Sudanese gold, according to the Washington-based Institute for the Study of War.

US President Joe Biden on Tuesday urged Sudan’s warring sides to halt attacks that are harming civilians, allow unhindered humanitarian access and restart talks to end the conflict.