The United States and ten South East Asia nations have agreed to deepen their trade and investment ties in a move that should help pave the way for more countries to link up with the Trans-Pacific Partnership (TPP) trade pact.

The US-ASEAN Expanded Economic Engagement (E3) initiative was launched on Monday (19 November) at a meeting in Phnom Penh, Cambodia between President Obama and leaders of the ten member states of the Association of Southeast Asia Nations (ASEAN).

The agreement aims to simplify customs procedures, and will see the joint development of investment, information and communications technology principles to help guide policymakers.

With a population of approximately 620m and a combined GDP of over $2.2 trillion, ASEAN is the US's fourth largest export market and fifth largest trade partner.

Currently four members of ASEAN - Singapore, Brunei, Malaysia and Vietnam - are participating in the Trans-Pacific Partnership (TPP) trade pact. Other ASEAN members include Cambodia, Indonesia, Laos, Myanmar (Burma), the Philippines and Thailand.

Other countries currently involved in the TPP talks are Chile, New Zealand, Australia, and Peru, with Canada and Mexico poised to join in December.

Another grouping - the Regional Comprehensive Economic Partnership (RCEP) - has also taken a step forward this week and could eventually lead to the largest regional trading arrangement in the world.

As well as ASEAN leaders, the RCEP involves six regional free-trade partners including China and India, as well as Australia, South Korea, Japan and New Zealand.