SINGAPORE (CNN) -- In a wide-ranging speech to university students, U.S. President George Bush pushed trade and regional cooperation as he kicked off a three-nation tour of Asia on Thursday.

Speaking at the National University of Singapore Bush pushed his theme: "Working Together To Build More Hopeful Societies In The Asia-Pacific Region."

The president's speech focused on the U.S. commitment to Asia in the areas of trade, terrorism, economic development and the pandemics of HIV and avian flu, while rejecting any notion of isolationism.

"America will remain engaged in Asia because our interests depend on the expansion of freedom and opportunity in this region," Bush said.

"Our trade across the Pacific is greater than our trade across the Atlantic, our businesses see a bright future in Asia's thriving economies and rising middle class, and we see threats like terrorism, proliferation, and disease that have the potential to undermine our prosperity and put our future in doubt."