Saleh's foreign policy as the leader of North Yemen was characterized by the principles of positive neutrality and Arab unity. Under Saleh, Yemen cultivated close ties with Saudi Arabia and other pro-West states in the region. He also purchased military equipment from the United States and expanded economic relations with the West. At the same time, Saleh also tried to maintain friendly relations with the then-Soviet Union (which broke apart in 1991). In October 1984, he renewed the treaty of Friendship and Cooperation that was originally signed in 1964 by San'a and Moscow.