Demonstrators shout slogans during a protest against the Trans-Pacific Partnership (TPP) with the slogan "Chile better without TPP" at Citizenship Square in Santiago, capital of Chile, on Feb. 4, 2016. Hundreds of Chileans protested on Thursday in front of presidential palace of La Moneda in Santiago against the TPP, which Chile signed on Thursday with other 11 nations in New Zealand. (Xinhua/Jorge Villegas)

WASHINGTON, Aug. 2 (Xinhua) -- U.S. President Barack Obama on Tuesday vowed to push Congress to approve the Trans-Pacific Partnership (TPP) trade agreement despite opposition from presidential nominees in both parties.

"Right now, I'm president and I'm for it, and I think I've got the better argument," Obama said of the controversial Pacific trade deal during a White House press conference with visiting Singapore's Prime Minister Lee Hsien Loong.

Obama wants Congress to approve the TPP trade deal to cement his trade legacy before he leaves the White House on Jan. 20. But Republican presidential nominee Donald Trump and his Democratic rival Hillary Clinton have both expressed their opposition to the 12-nation deal.

Obama acknowledged that some past U.S. trade deals had not delivered on all the benefits that were promised and had very localized costs, but he urged Americans not to cut off globalization.

"The answer is, how do we make sure that globalization, technology, automation, those things work for us, not against us? And TPP is designed to do precisely that," he argued, adding that enforceable labor and environment provisions were included in the TPP trade agreement.

"Hopefully, after the election is over and the dust settled, there will be more attention to the actual facts behind the deal and it won't just be a political symbol or a political football," he said.

Senate Majority Leader Mitch McConnell said last month that chances for the TPP agreement to get a vote in Congress this year were "pretty slim," including in the so-called "lame duck" session after the November general election, suggesting that the upper chamber could wait until the next president takes office.

Lee warned at the press conference that the U.S. could lose its reputation and harm U.S. relations with its allies in Asia if the country failed to ratify the TPP trade deal.

"I think in terms of America's engagement of the region, you have put your reputation on the line. It is the big thing which America is doing in the Asia-Pacific with the Obama administration consistently over many, many years of hard work and pushing," Lee said.

"If at the end, waiting at the altar the bride doesn't arrive, I think there are people who are going to be very hurt. Not just emotionally, but really damaged for a long time to come," he added.

The TPP involves Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, the United States and Vietnam.