An Iranian official said “Republican rivals of the current US administration” attempted to stall last month’s Iranian-U.S. prisoner swap until the eve of the U.S. presidential election, Tasnim News Agency reported.

According to the semi-official Iranian news outlet, Ali Shamkhani, the secretary of Iran’s Supreme National Security Council, made the claims during a speech Thursday at a rally in Yazd, Iran.

“In the course of the talks for exchanging prisoners, the Republican rivals of the current US administration who claim to be humanitarians and advocates of human rights sent a message telling us not to release these people [American prisoners] and continue this process [of talks] until the eve of US presidential elections,” Shamkhani said, according to Tasnim.

“We acted upon our independent resolve and moved the process forward,” Shamkhani said.

The prisoner swap Shamkhani referred to included Washington Post journalist Jason Rezaian and three other U.S. citizens imprisoned in Iran, who were freed in exchange for the release of seven Iranians.

The swap was negotiated alongside the White House’s nuclear deal with Iran, and the prisoners were released just before the economic sanctions on Iran were set to lift as part of the nuclear deal.