From Reuters:
Obama said he still believed side agreements on labor and environmental protections should be incorporated into the core of the agreement.
"But I will be honest with you: at a time when the economy has been shrinking drastically and trade has been shrinking around the world, at a time when Mexico has suffered a double-digit blow because not only of a declining economy but because of the effects of H1N1 on tourism, we probably want to make the economy more stabilized in the coming months before we have a long discussion around further trade negotiations."
...
"In terms of refining some of our agreements, that is not where everyone's focus is right now because we are in the middle of a very difficult economic situation," Obama said, while adding that he was still interested in learning where the treaty can be improved.