The U.S.-Colombia Trade Promotion Agreement will become effective May 15, President Barack Obama announced Sunday, during the two-day Summit of the Americas in Cartagena, Colombia.

This agreement will provide American businesses, farmers, and ranchers with significantly improved access to the third-largest economy in South America, U.S. Trade Representative Ron Kirk said in a statement.

Last year, the U.S. had gross domestic product of $15.06 trillion and Colombia had GDP of $321.5 billion, according to estimates in the CIA's World Factbook.

Nonetheless, Kirk said: One month from today, the value of the U.S.-Colombia trade agreement will begin to be seen in lower tariffs on autos, consumer goods, agricultural commodities, machinery, and other exports from the United States, which will make our goods more competitive in the Colombian market. That means support for well-paying jobs at home.

Colombian President Juan Manuel Santos was also effusive about the pact, according to Reuters, which noted he said free trade with the U.S. had been a Colombian dream for 20 years that has finally come true.

At a news conference with Obama, Santos said, This will create thousands, millions of jobs in the United States and Colombia, Reuters reported.

However, the politically powerful AFL-CIO took a dim view of the U.S.-Colombia free-trade agreement, with the labor organization's president, Richard Trumka, calling its implementation deeply disappointing and troubling.

In a joint statement, Trumka, Central Unitaria de Trabajadores de Colombia President Luís Miguel Morantes, and Confederacion de Trabajadores de Colombia President Tarcisio Mora Godoy said:

We have been monitoring the progress of the Action Plan [on Labor Rights] and conclude that, although new laws and directives are in place, the Government of Colombia has not yet demonstrated successful implementation.

Workers across the whole economy continue to be forced into indirect employment relationships -- preventing them from exercising their rights to free association and collective bargaining -- because the Government has not completely lived up to its promises regarding cooperatives and other employment relationships that affect labor rights.

Nor has the Government of Colombia compiled a successful record of criminal prosecutions of employers who illegally interfere with workers' fundamental rights. Labor activists and other human rights defenders remain subject to threats and violence, including murder, when they stand up to fight for their rights.

About two dozen Colombian union leaders were killed last year alone, according to the AFL-CIO.