In July 1988, Khomeini, in his words, "drank the cup of poison" and accepted a truce mediated by the United Nations. Despite the high cost of the war – 450,000 to 950,000 Iranian casualties and US$300 billion – Khomeini insisted that extending the war into Iraq in an attempt to overthrow Saddam had not been a mistake. In a "Letter to Clergy" he wrote: "... we do not repent, nor are we sorry for even a single moment for our performance during the war. Have we forgotten that we fought to fulfill our religious duty and that the result is a marginal issue?"