President Obama announced Sunday that Colombia has complied with a key condition of the free-trade agreement passed last year that is designed to better protect labor activists.

The certification allows the deal to take effect May 15. U.S. exports to Colombia last year totaled $14.8 billion, and the agreement will eliminate tariffs on 80 percent of U.S. consumer and industrial goods bound for the country and phase the rest out over the next decade.

But the election-year decision has angered U.S. labor leaders, who say Colombia has not made enough progress in protecting union activists in Colombia and in punishing those who commit crimes against them.

In a letter to Obama last week, AFL-CIO President Richard Trumka wrote that "less than 10 percent of the nearly 3,000 cases of trade unionists' murders since 1986 have reached a conviction" and that "none of the 29 labor activists killed in 2011 had their cases resolved by a successful prosecution."