Israel says it will prosecute dozens of pilgrims returning from Ukraine who flew back into the country with fake negative Covid test results.The pilgrims had been attending the annual celebration of the Jewish new year, Rosh Hashanah, in the Ukrainian city of Uman, where Rabbi Nachman of Breslov, who founded the Hasidic Breslov sect in the early 19th century, is buried. He was a great-grandson of the founder of Hasidism.Between 25,000 and 30,000 pilgrims, largely from the Breslov sect, visited Uman in central Ukraine this year. Israel’s Magen David Adom medical service told the Jerusalem Post that up to 14% of those returning had tested positive for Covid.The medical service, which had set up testing centres in Uman and at the airport in Kyiv, said 2,000 pilgrims coming back from the Ukrainian city had tested positive for Covid. The service had sent a team of more than 100 medics and paramedics to Uman at the request of the Israeli government to help test the pilgrims.After a tipoff, police identified pilgrims with fake paperwork as they arrived in Israel, escorting them home for mandatory quarantine amid fears that hundreds could have procured bogus tests.The Israeli border and immigration service said it had received information that dozens of people who tested positive in Ukraine had boarded planes with false negative tests. On just one flight from Kyiv, 13 passengers were found to have forged tests, the Ynet website reported.The prime minister, Naftali Bennett, condemned the scam. “The Israeli government takes a very serious view of patients who fraudulently enter Israel by falsifying documents and deliberately spread disease, which constitutes an irresponsible act of harming public peace,” his office said.Breslov Hasidic pilgrims processing through the streets in Uman on 7 September. Photograph: Ukrinform/RexBennett said anyone caught using forged paperwork would be prosecuted, including potential charges of fraud, forgery and deliberately spreading disease.The scandal comes at a sensitive time in Israel, which hoped that the latest wave of the Covid pandemic, driven by the Delta variant, had been brought under control.According to reports in Israeli media, pilgrims who had received positive Covid tests at crowded testing centres in Uman before returning home were later approached with offers of forged documents for their journey.The health ministry director general, Nachman Ash, said: “We are hearing that there are not a small number of infected people, those that tested positive over there, and we expect more people to be diagnosed here, too.”The Uman pilgrimage is the latest large religious festival to be implicated in spreading infection. The Hindu festival Kumbh Mela was last year blamed for increasing infections in India and Nepal, while pilgrims to the Iranian city of Qom were implicated in the early spread of Covid in Iran.