The head of the World Trade Organization says growing Asian protectionism is the biggest threat to sustained economic growth in the region.

WTO Director-General Pascal Lamy told the opening session of the World Economic Forum on East Asia Thursday that deeper trade integration among Asian nations is key to making the region more resilient to a slowing global economy.

Lamy acknowledged that the Asian economy has been “doing better than the rest of the world.” But he said it is not immune to the economic uncertainty in the United States and Europe and a slowing economy in China.

“I would expect, given what's happening in other parts of the world economy, for this region to be more affected in two, three years to come than it has been so far.”

Other leaders at the summit expressed skepticism about increased regional integration.

Thai Deputy Prime Minister Kittiratt Na-Ranong warned against focusing too much on export-led growth, saying Asian countries must be able to grow their own economies before they can help others.

The two-day economic summit in the Thai capital, Bangkok, began Thursday. It is aimed at providing a forum for nations and business leaders to discuss issues of regional concern.