network in Afghanistan. Some 29 pages from the collection were purchased by the Jerusalem-based National Library of Israel in 2013. Soviet refugee crisis By the early 1930s, some 60,000 refugees fled from the Soviet Union and reached Afghanistan. In 1932, Mohammed Nadir Shah signed a border treaty with the Soviets in order to prevent asylum seekers from crossing into Afghanistan from Soviet Central Asia. Later that year, Afghanistan began deporting Soviet-origin refugees either back to the Soviet Union or to specified territories in China. Soviet Jews who were already present in Afghanistan with the intent to flee further south were detained in Kabul, and all Soviet Jews who were apprehended at the border were immediately deported. Soviet Jews were accused of conducting espionage with the intention to disseminate radical Bolshevik propaganda. Anti-Jewish campaign Mohammed Nadir Shah was assassinated in 1933 and was succeeded by his son, Mohammed Zahir Shah, who expanded his father's campaign against the Jews of Afghanistan. Afghan Jews were declared non-citizens and targeted for persecution. All Jewish citizens of Afghanistan were ordered to relocate to their city of birth, which was most often Herat or Kabul. This was an attempt by the government to further enforce the policy that Jews did not belong in the northern provinces of Afghanistan. By the end of 1933, nearly all Jews in Afghanistan's northern cities had been expelled and returned to central Afghanistan. Many Jews in Afghanistan were expelled from their homes and robbed of their property, but continued to live in major cities such as Kabul and Herat under restrictions on work and trade. In 1935, the Jewish Telegraphic Agency reported that "ghetto rules" had been imposed on Afghan Jews, requiring them to wear particular clothes, requiring Jewish women to stay outside markets, requiring all Jews to live within certain distances from mosques and banning Jews from riding horses. In 1935, a delegate to the World Zionist Congress said that an estimated 40,000 Bukharan Jews had been killed or starved to death. In mid-1935, riots erupted in Herat, the Afghan city with the largest Jewish population, over a dispute between two boys— one Jewish and one Muslim. The two boys got into a fight for unknown reasons, during which the Muslim boy fell down a flight of stairs. The Jewish boy, Aba ben Simon, was blamed, and others began spreading rumors that he was trying to convert the Muslim boy