U.S. President Barack Obama and his South Korean counterpart are hailing Thursday's inauguration of a long-stalled free trade agreement.

The pact, known as the Korea-U.S. Free Trade Agreement, was signed in 2007, but not approved by lawmakers in either country until late last year due to political opposition and changes of government in both countries.

The White House says Mr. Obama called President Lee Myung-bak on Thursday to thank him for his “close cooperation” in getting the agreement implemented.

Mr. Obama said the deal is a strong example of the countries' partnership, and that it will boost investment, trade and jobs in both nations, while helping to tear down trade barriers around the world.

The pact will eliminate tariffs on more than 7,000 South Korean products and nearly 62,000 American goods and services. South Korea says it will create 350,000 jobs and expand the country's GDP by nearly six percent over the next 10 years.

But the agreement still faces fierce opposition by many in South Korea, who say it will hurt farmers and small retailers. South Korea's main opposition party has promised to renegotiate the deal if it wins December's presidential election.

On the eve of its implementation, about 1,500 people held a rally in Seoul to protest the deal, saying protests will continue until the pact is nullified. A smaller group of pro-FTA activists also gathered in the South Korean capital to celebrate the deal.

It is the most significant pact for the United States since a 1994 North America Free Trade Agreement with Canada and Mexico.