Iran has brokered ongoing secret talks between Russia and Yemen's Houthi rebels to transfer anti-ship missiles to the militant group, three Western and regional sources said, a development that highlights Tehran's deepening ties to Moscow.

Seven sources said that Russia has yet to decide to transfer the Yakhont missiles — also known as P-800 Oniks — which experts said would allow the militant group to more accurately strike commercial vessels in the Red Sea and increase the threat to the U.S. and European warships defending them.

The Wall Street Journal reported in July that Russia was considering sending the missiles. Iran's role as an intermediary has not been previously reported.