The crisis quickly became the subject of international and domestic attention, and Carter vowed to secure the release of the hostages. He refused the Iranian demand of the return of Pahlavi in exchange for the release of the hostages. His approval ratings rose as Americans rallied around his response, but the crisis became increasingly problematic for his administration as it continued. In an attempt to rescue the hostages, Carter launched Operation Eagle Claw in April 1980. The operation was a total disaster, and it ended in the death of eight American soldiers. The failure of the operation strengthened Ayatollah Khomenei's position in Iran and badly damaged Carter's domestic standing. Carter was dealt another blow when Vance, who had consistently opposed the operation, resigned. Iran refused to negotiate the return of the hostages until Iraq launched an invasion in September 1980. With Algeria serving as an intermediary, negotiations continued until an agreement was reached in January 1981. In return for releasing the 52 captives, Iran accepted over $7 billion in monetary compensation and the unfreezing of Iranian assets in the United States. Iran waited to release the captives until hours after Carter left office on January 20, 1981.