Mr. Ambassador:
I am happy to receive from Your Excellency the letters by which the Presidium of the Supreme Soviet of the Union of Soviet Socialist Republics accredits you as Ambassador Extraordinary and Plenipotentiary of the Union of Soviet Socialist Republics to the Government of the United States, and I welcome you in that capacity.
I am deeply gratified at the expression of your determination to develop further the friendly relations of understanding and confidence which so happily exist between our two countries, and continue thereby the work of your distinguished predecessor whose letters of recall you have handed to me. I can assure you, that in the performance of this high task with which your Government has entrusted you, Your Excellency may count upon receiving the full cooperation and support of the Government of the United States.
The fortitude, courage, and self-sacrifice of the armed forces and people of the Soviet Union in their terrible hours of trial have aroused the undying admiration of the American people, and we rejoice with the people of the Soviet Union in the ever growing tide of success which is crowning Soviet arms.
Since the day of the treacherous assault upon your country by Nazi Germany it has been, and it is, the unswerving intention of this country to lend maximum assistance to your gallant armies. Our two countries are united against a common enemy. The Government and people of the United States have bent every effort to bring to bear as speedily and as effectively as possible the might of our armed forces against that enemy.
The enemy has felt, is feeling, and will to an ever increasing degree feel the weight of the combined forces of the United Nations, and when the final and complete victory is achieved, as it will be, I know that every one of the United Nations will have made its full contribution toward that victory.
Our countries are joined together in a high cause, and I fully share your confidence that the unity of purpose which binds our peoples and countries together in the prosecution of the war will be translated into a close and lasting collaboration, together with other like-minded countries, in the establishment of a just and enduring peace.
Franklin D. Roosevelt, Remarks to Ambassador Gromyko of Russia. Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/209578