PHNOM PENH - In the backdrop of a historic visit by US President Barrack Obama, the 21st ASEAN summit closed in Phnom Penh on Tuesday after making significant strides on key trade, human rights and regional disputes.

Obama, the first ever sitting president to visit Cambodia, during talks with Association of South East Asian Nations (ASEAN) leaders pledged to engage in a range of issues including economic and security aspects.

ASEAN Secretary General Dr Surin Pitsuwan in a brief interaction with media after the US ASEAN meeting remarked that Obama had stated the US would support the centrality of the bloc.

"ASEAN leaders welcomed the statement on supporting ASEAN centrality in the evolution of cooperation in the region. The US also pledged to engage economically and work on security stability in the region."

Assuring of a long engagement Obama had remarked on the rapid increase in relations between the two sides and insisted that continued meetings would result in more extensive engagement.

"All leaders were enthusiastic of more extensive relations and continuous summits that would lay down irreversible momentum for US and ASEAN relations," he said.

Another important aspect that was highlighted was ASEAN's adoption of a Human Rights Declaration. However the document ran into criticism from activists that insisted it was too flawed to be passed but Cambodian Foreign Affairs Minister Hor Namhong was emphatic that it was a "starting point" for the region to address human rights concerns.

More than 50 local and international rights groups criticized the document insisting that the signing should have been postponed so that the declaration could be redrafted.

In response to criticism, ASEAN foreign ministers decided to add a paragraph to the Declaration at the last minute expressing that it would abide by the stipulations of the Universal Declaration of Human Rights but won few fans for the effort.

On the economic front, ASEAN and its partners on Tuesday launched negotiations of a comprehensive partnership agreement that when completed will be the world's biggest regional free trade deal.

Australia, China, India, South Korea, Japan and New Zealand, officially kicked off negotiations for the Regional Comprehensive Economic Partnership or RCEP at the final day of the 21st Association for South East Asian Nations (ASEAN). The idea was first mooted at the 19th ASEAN Summit in November 2011.

The significant progress made in ASEAN's FTAs with China (ACFTA) , Japan (AJCEP), Korea (AKFTA), India (AIFTA), and Australia and New Zealand (AANZFTA) has put these trading partners in a position to bring to a higher level economic partnership.

When completed the RCEP will span 16 countries with a combined market of over 3 billion people and a combined GDP of about $19.78 trillion based on 2011 figures.

"With the region accounting for more than half of the global market and about a third of the global economic output, there is no doubt that a successful RCEP would significantly contribute and boost global trade and investment," said Dr. Pitsuwan.

RCEP negotiations are expected to commence in 2013.

In addition it was reported that South Korea, China and Japan had also agreed to form a free trade agreement at the summit, which is expected to formally begin next year.

Malaysia and Indonesia during bilateral meetings with China called for more investment from the world's fastest growing economy and promised to fast track trade agreements.

Trade between ASEAN and China is set to continue its expansion with the bloc's largest trade partner encouraged to step up investment in the region.

"We are hoping for more investment from China. Even though trade has grown tremendously the trade deficit and trade gap between ASEAN and China is larger than in some other regions," Dr Pitsuwan said.

Trade between China and ASEAN has sky-rocketed from $7.9 billion in 1991 to $292.7 billion in 2010.

The FTA between ASEAN and China became effective in 2010.

Smaller countries such as Myanmar also progressed on economic agreements. On Monday Thailand and Myanmar signed a joint agreement to move ahead with the multi-billion dollar Development of Dawei Special Economic Zone (DSEZ). Japan and India have also expressed interest in jump starting trade and investment relations with the fast-changing nation.

An eventful 21st ASEAN summit concluded with Cambodia ceremoniously handing over the chairmanship to Brunei, passing on the responsibility of meeting the demanding target of an ASEAN community by 2015 and setting the stage for intensified engagement as Asia continues to spearhead world growth.