WASHINGTON ( CNN ) -- The State Department 's chief of diplomatic security has resigned amid scrutiny of the use of private military contractors to guard the department 's staff in Iraq , a spokesman said Wednesday . Richard Griffin testifies before a House committee looking into private security contractors earlier this month . Richard Griffin , a 36-year career official , gave no explanation for his decision in his resignation letter to President Bush . `` I am grateful that I had the opportunity to serve as the assistant secretary for the Bureau of Diplomatic Security , whose brave men and women serve on the front lines of the Global War on Terror , '' he wrote in his resignation letter , a copy of which was obtained by CNN . `` Without their courage and commitment , the State Department could not possibly carry out its foreign policy mission . '' Secretary of State Condoleezza Rice accepted Griffin 's resignation , State Department spokesman Sean McCormack said . Griffin 's decision to step down follows weeks of investigations into the September 16 killings of Iraqi civilians by Blackwater USA , a North Carolina-based firm hired by the State Department to protect American diplomats in Baghdad . Meanwhile , a survivor of the September 16 incident told CNN on Wednesday that he and a number of other victims were summoned to a meeting with U.S. Embassy officials and were offered money . Mohammed Abdul Razzaq , whose 9-year-old son died , said the embassy offered him $ 12,500 -- which he said he refused because `` they did n't acknowledge their crime . '' `` Do n't they need to acknowledge my son 's blood first so I can forgive them ? Now I ca n't . How can I take compensation and they never acknowledge the crime ? '' he said . The father is demanding a formal apology from Blackwater CEO Erik Prince , prosecution of those responsible for his son 's death and political asylum in the United States so he can pursue the case in American courts . Another survivor , taxi driver Sami Hawas , told CNN he received $ 7,500 from the embassy , a payment he described as `` aid . '' Hawas was shot a number of times in the back and leg . He said he is unable to work now and complained about the high cost of medication . He took the money , he said , because he needs help paying for medical treatment and supporting his family . `` Even if they compensate me with millions , it will not make up for the lost blood and the pain I live every day , '' he told CNN . U.S. Embassy spokeswoman Mirembe Natango said the payments were `` part of a standard procedure '' and would continue . She described them as `` short-term and speedy aid and support '' but said they were not an admission of guilt . She said those receiving the money do not waive any right to future compensation . The State Department and the FBI are conducting their own investigation into the killings , and a joint U.S.-Iraqi commission is reviewing the results of both probes . Prince has said that Blackwater guards came under fire while protecting a State Department convoy and acted properly in self-defense . Watch Blackwater chief talk about his company » . But Iraqi authorities have called the killings `` premeditated murder '' and demanded Blackwater leave Iraq . A State Department report of its own operations , released Tuesday , found lax oversight of security contractors , who are under the supervision of the Bureau of Diplomatic Security . It recommended tightening the rules of engagement for contractors to bring them in line with those used by the U.S. military , and Rice appointed a top U.S. diplomat to oversee all security operations in Iraq . Blackwater is the most prominent of the military contractors working in Iraq , where an estimated 25,000 private contractors guard diplomats , reconstruction workers and government officials . Company officials urged subscribers to its e-mailed newsletter Wednesday to help fight its public-relations battle . `` In this tumultuous political climate , Blackwater Worldwide has taken center stage , our services and ethics aggressively challenged with misinformation and fabrications . Letters , e-mails and calls to your elected congressional representatives can and will create a positive impact by influencing the manner in which they gather and present information , '' the company wrote . The message , titled `` A Request for Your Support , '' urged readers to contact members of Congress `` and tell them to stand by the truth . '' It recommended that constituents emphasize that the company hires U.S. military veterans and the fact that no one under Blackwater 's protection has been killed in Iraq . It also asked that supporters stress what the company termed the `` cost efficiency '' of its services , for which the State Department has paid more than $ 800 million since 2004 . Blackwater spokeswoman Anne Tyrrell said the company had received `` hundreds of positive responses '' to its appeal by Wednesday afternoon . The contractors are immune from prosecution under Iraqi law , under an order issued by the American-led occupation government in 2004 . Iraq 's government has agreed to ask the country 's parliament to consider changing that directive , an adviser to Prime Minister Nuri al-Maliki told CNN on Wednesday . E-mail to a friend . CNN 's Jomana Karadsheh , Elise Labott , Ingrid Formanek , Jim Clancy and Saad Abedine contributed to this report .
Assistant secretary of state for diplomatic security announces decision to resign . Richard Griffin gave no specific reason for resignation or offered timetable . Blackwater issues appeal to supporters to stand up for company . NEW : Blackwater shooting survivor says U.S. Embassy offered victims money .