The United Nations envoy for Syria has resigned after two years of failed efforts to mediate an end to the country’s civil war. Lakhdar Brahimi will formally step down at the end of the month. Brahimi offered parting words after his final address to the Security Council.

Lakhdar Brahimi: “I am sure that the crisis will end. The question is only, and this everybody who has a responsibility and an influence in the situation have to remember, that the question is: How many more dead? How much more destruction there is going to be before Syria becomes again the Syria we have known? The new Syria that will be different from the Syria of the past, but it will be the Syria we have loved and admired for many, many years.”

The Syrian conflict has killed more than 150,000 people and left millions displaced. Brahimi had repeatedly threatened to step down as talks between the Assad regime and opposition rebels failed to get off the ground. On Tuesday, Secretary-General Ban Ki-moon paid tribute to Brahimi’s efforts.

Secretary-General Ban Ki-moon: “Mr. Brahimi has long been recognized as one of the world’s most brilliant diplomats as well as outstanding proponent of the principles of the Charter of the United Nations. That the objective to which he applied his extraordinary talents has proven elusive is a tragedy for the Syrian people. That his efforts have not received effective support from the United Nations body that is charged with upholding peace and security, and from countries with influence on the Syrian situation, is a failure of all of us.”