by Ding Yi BEIJING, July 23 (Xinhua) -- Agreement to the Treaty of Amity and Cooperation by the United States indicates America has re-engaged with Southeast Asia and will regain interests in the region, a Chinese analyst said Thursday. Meanwhile, due to mutual demands between the United States and Southeast Asian countries, the move also will strengthen bilateral cooperation in the fields of economy, trade and climate change, said Guo Xiangang, a scholar from the China Institute of International Studies. A U.S. presence in Southeast Asia would complicate and bring uncertainties to regional issues, Guo said. STRATEGIC DEPLOYMENT U.S. Secretary of State Hillary Clinton signed the friendship pact with member states of the Association of Southeast Asia Nations (ASEAN) in Thailand's Phuket on Wednesday in what is seen as America's return to the 'critically important' region. Clinton said the Obama administration wanted to send a strong message of engagement after the region had been neglected by former President George W. Bush during the wars in Iraq and Afghanistan. The new U.S. approach was demonstrated by her first overseas trip as the top U.S. diplomat to Asia in February, Clinton said, adding that Washington views the amity treaty as a symbolic underscoring of American commitment to Asia. Guo said that the U.S. return to Southeast Asia is part of a multilateral diplomatic policy proposed by the Obama administration, which is considered a revision of Bush's unilateral policy. The United States wants to participate in the region's development process to show its clout in the area and to help solve problems such as the Korean Peninsula nuclear issue and Myanmar's ongoing political instability, the researcher said. 'If the United States does not take part in the process, it can not effectively impose its influence in the region,' he said. MUTUAL DEMANDS On the one side, the signing of the treaty means the Americans would regain interests in Southeast Asia, the sixth largest U.S. export market and an important strategic stronghold with abundant oil and energy resources. On the other side, Southeast Asian countries welcomed the U.S. participation in the region's development process, during which they would get the biggest possible interests as they can, Guo said. 'Southeast Asian countries tried to use big powers and strategic balance to seek their own security and stability,' the analyst said. The cooperation between the United States and the four Mekong downriver countries -- Cambodia, Laos, Thailand and Vietnam -- shows that the Americans attach importance to the region, said Yue Yang, a Vietnamese researcher. ASEAN leaders have also hailed U.S. accession to the amity treaty. 'We warmly welcomed the impending accession by the United States of America to the Treaty of Amity and Cooperation in Southeast Asia as a strong signal of its commitment to peace and security in the region,' said a joint communique issued Monday after the ASEAN ministers' meeting. POTENTIAL COMPLICATION The row between the United States and Myanmar over the case of Aung San Suu Kyi, who was facing trial for violating her terms of house arrest by accommodating a U.S. citizen, has been spotlighted since May. Myanmar's government leaders have frequently said that the legal action against Aung San Suu Kyi is an internal affair which is in accordance with its domestic law, accusing the United States of meddling in its internal affairs. Clinton called on Myanmar, which has put Suu Kyi, general secretary of the National League for Democracy, under a five- and-a-half-year house arrest, to free her and take other steps to ensure a credible general election next year. The Myanmar authorities have blamed the U.S. citizen, identified as John William Yettaw, for the current trial involving Aung San Suu Kyi. Meeting with the press, Myanmar Police Chief Brigadier-General Khin Yi charged Yettaw with illegally intruding into Aung San Suu Kyi's residence which was then under restriction and held him mainly accountable for the case. Analysts said the U.S.-Myanmar spat brought uncertainty and complication to the region's development. Clinton views ASEAN as a region of 'great diversity where people of different backgrounds, religions and every other diversities of the human experience are working to build a community.' Moreover, Clinton talked about the nuclear issues of the Democratic People's Republic of Korea and Iran at the ASEAN foreign ministers' meeting, a sign indicating that the U.S. return to Southeast Asia is broader than expected, analysts said. 