Australia has devoted particular attention to relations between developed and developing nations, with emphasis on the countries of the Association of Southeast Asian Nations (ASEAN) – Indonesia, Singapore, Malaysia, Thailand, the Philippines, and Brunei – and the island states of the South Pacific. Australia is an active participant in the ASEAN Regional Forum (ARF), which promotes regional co-operation on security issues. Australia was a participant at the inaugural ASEAN sponsored East Asia Summit in 2005. Australia's place at the summit was only secured after it agreed to to ASEAN's Treaty of Amity and Cooperation in Southeast Asia. Australia had been reluctant to sign the treaty out of concerns regarding how it would affect Australia's obligation under other treaty arrangements including ANZUS.