SAN FRANCISCO — Facebook said Thursday that it had ended its relationship with a Washington-based consulting firm, Definers Public Affairs, which spread disparaging information about the social network’s critics and competitors.

The move followed a New York Times article on Wednesday that described the kind of work that Definers did on Facebook’s behalf. Among other things, Definers worked to discredit activist protesters who were against Facebook, in part by linking them to the liberal financier George Soros. It also tried to deflect criticism of the social network by pressing reporters to look into rivals like Google.

Late Wednesday, Facebook decided to terminate its relationship with Definers after the publication of the Times article prompted an outcry, said a person familiar with the matter, who was not authorized to speak publicly. Top Facebook executives including Mark Zuckerberg and Sheryl Sandberg were not aware of the specific work being done by Definers, the person said.

In a statement, Facebook said it had not hidden its ties to Definers and disputed that it had asked the firm to spread false information.