İnönü wanted Turkey to join the UK-inspired "peace front" that was meant to stop Germany. On 24 June 1939, France and Turkey signed a declaration committing them to upholding collective security in the Balkans. On 21 August 1939, Papen presented Turkey with a diplomatic note threatening economic sanctions and the cancellation of all arms contacts if Turkey did not cease leaning towards joining the UK-French "peace front", a threat that Turkey rebuffed. On 1 September 1939, Germany invaded Poland and two days later on 3 September 1939 the UK and France declared war on Germany. Papen claimed later to have been opposed to Hitler's foreign policy in 1939 and was very depressed when he heard the news of the German attack on Poland on the radio. Papen continued his work of representing the "Reich" in Turkey under the grounds that resigning in protest "would indicate the moral weakening in Germany", which was something he could never do. On 19 October 1939, Papen suffered a notable setback when Turkey signed a treaty of alliance with France and the UK. During the Phoney War, the conservative Catholic Papen found himself to his own discomfort working together with Soviet diplomats in Ankara to pressure Turkey not to enter the war on the Allied side. In June 1940, with France's defeat, İnönü abandoned his pro-Allied neutrality, and Papen's influence in Ankara dramatically increased. Between 1940 and 1942 Papen signed three economic agreements that placed Turkey in the German economic sphere of influence. Papen hinted more than once to Turkey that Germany was prepared to support Bulgarian claims to Thrace if Turkey did not prove more accommodating to Germany. In May 1941, when the Germans dispatched an expeditionary force to Iraq to fight against the UK in the Anglo-Iraqi War, Papen persuaded Turkey to allow arms in Syria to be shipped along a railroad linking Syria to Iraq. In June 1941, Papen successfully negotiated a Treaty of Friendship and Non-aggression with Turkey, signed on 17 June 1941, which prevented Turkey from entering the war on the Allied side. After Operation Barbarossa, the invasion of the Soviet Union that began on 22 June 1941, Papen persuaded Turkey to close the Turkish straits to Soviet warships, but was unable to have the straits closed to Soviet merchant ships as he demanded. Papen claimed after the war to have done everything within his power to save Turkish Jews living in countries occupied by Germany from deportation to the death camps, but an examination of the "Auswärtige Amt"'s records do not support him.