The United States was not aware of ongoing negotiations between al Qaeda-affiliated militants in Yemen and Gift of the Givers -- a humanitarian aid organization -- over the release of Pierre Korkie, the South African national killed on Saturday during a failed attempt to rescue American hostage Luke Somers, the U.S. ambassador in South Africa said on Monday, according to media reports.

Ambassador Patrick Gaspard was responding to an earlier statement by Gift of the Givers, a South African charity working toward Korkie’s release, in which it said that the negotiations over Korkie’s release were in the final stages and that “all logistical arrangements were in place to safely fly Pierre out of Yemen under diplomatic cover.” Officials from Gift of the Givers reportedly said that Korkie was to be released on Sunday, and that the U.S. operation had “destroyed everything.”

“We were just completely unaware of those developments and had to act hastily,” Gaspard told The Associated Press on Monday, adding that it was “not altogether clear” to him that even the South African government was aware of the talks.

Korkie, a former college teacher from Bloemfontein in South Africa, was abducted along with his wife Yolande in May 2013, according to media reports. While Yolande was released in January without ransom, the al Qaeda militants holding Pierre reportedly demanded $3 million for his release.

The South African government on Sunday said that it was “deeply saddened” by Korkie’s death and urged people to refrain from “fingerpointing,” according to a report by BBC.

“We are working with the government of the United States as well as the government of Yemen, to ensure that we bring finality to this tragic incident,” Nelson Kgwete, a spokesperson for the South African government, reportedly said.