A gay rights bill was derailed at the last minute by a bloc of conservative senators, but supporters vowed to revive the legislation.
The bill, which had been endorsed by conservative President Alvaro Uribe, would have made Colombia the first nation in Latin America to grant gay couples in long-term relationships the same rights to health insurance, inheritance and social security as heterosexual couples,
Slightly different versions of the bill had been approved by Colombia's Senate and house of representatives and Tuesday's vote on the final, coordinated version was expected to be routine.
But in a surprise move, Sen. Manuel Virguez Piraquive, from a small party closely linked to an evangelical Colombian church, called for an unusual floor vote on the bill.
Other conservative lawmakers then broke ranks with the pro-Uribe faction backing the bill and it was defeated, 34-29, in the 102-member Senate. Many of the bill's supporters were absent.
The call for individual votes was unusual, and some said unprecedented. Parties usually vote as blocs on the final, reconciled versions of bills in Colombia's legislature.
Sen. Armando Benedetti, a sponsor of the bill, vowed to restart the legislative process when Congress reconvenes on July 20, and he criticized Uribe for not defending the initiative more forcefully.
"He said he supported the bill during his presidential campaign, but since then he's been silent," Benedetti said.
Gay rights activists promised to protest the bill's derailment.
"This was clearly a trick to sink the bill," said Marcela Sanchez, head of Colombia Diversa, a gay rights group. "Never has a project reconciled by both chambers been called to a floor vote."
Although states and cities have passed similar laws allowing gay couples to share assets, no other country in the overwhelmingly Roman Catholic region has done so at a national level.
Colombia's Constitutional Court recognized similar rights to shared property and inheritance in a February ruling, but the decision did not mention health insurance or social security.
While homosexuality is still taboo in much of Latin America, there has been increasing acceptance in many areas. Mexico City and the Mexican state of Coahuila recently joined the Argentine capital of Buenos Aires and the southern Brazilian state of Rio Grande do Sul in legalizing same-sex civil unions.
Opponents of the measure and representatives of the Roman Catholic Church said they feared the Colombian law would open the way to gay marriage and gay adoption.