Trade ministers from 12 Pacific Rim countries including the United States have ceremonially signed a free-trade deal.

The representatives gathered Thursday in Auckland, New Zealand, to sign the Trans-Pacific Partnership.

The agreement must still be ratified by individual countries.

In the U.S., the agreement has been at the center of President Obama's trade agenda, but Senate Majority Leader Mitch McConnell has not yet backed it and has suggested Congress shouldn't vote to ratify it until after the November elections.

The agreement covers an estimated one-third of all world trade. Noticeably missing from the agreement is China, which is forging ahead with its own trade deals.

Hundreds of people in New Zealand protested the signing Thursday. Many fear it will erode sovereignty and hand too much power to U.S. corporations.