Colombia has agreed in free-trade discussions with the United States to take steps to better protect union leaders, senior White House officials said Wednesday, potentially moving the deal forward.

Obama administration officials said the Colombian government has set out a series of labor reform milestones to complete by the end of the year. If met, the officials said, the White House would move ahead with the pending Colombia trade pact.

Colombia has a long history of violence against union organizers and a poor track record of investigation and prosecution of those responsible.

The George W. Bush administration negotiated the free trade agreement with Columbia in 2007. But the pact was never submitted to Congress because of growing skepticism about the value of free trade agreements to U.S. workers.

Administration officials said they hope to get congressional action on a free trade deal with South Korea and several other trade issues that have been complicated by congresssional demands for quicker completion of the Colombia agreement.