At about 1am on 24 August, Ahmed (not his real name) climbed into a rubber dinghy with 29 others and left Turkey’s north-western Çanakkale province. After 30 minutes, he said, they reached Greek waters near Lesbos and a panther boat from the Hellenic coastguard approached. Eight officers in blue shorts and shirts, some wearing black masks and armed with rifles, forced the group – more than half women and including several minors and six small children – to come aboard at gunpoint. They punctured the dinghy with knives and it sank. “They said they would take us to a camp,” said Ahmed. “The children were happy and started laughing, but I knew they were lying.” Through the course of the night, Ahmed, a 17-year-old refugee from Eritrea, alleges that Greek officers detained the group, confiscating possessions and denying them access to toilets and drinking water. By morning, they were dispatched into a liferaft in Turkish waters. It was too small, and videos taken by Ahmed, who hid his phone, show some people were forced to swim. The Turkish coastguard confirmed it intercepted the raft at 1:20pm. The event described by Ahmed, who fled conflict in Eritrea after his father died, was one of seven times that he says he has been pushed back by the Hellenic coastguard. The use of these “pushbacks” has surged since March according to an investigation by the Guardian, and experts say it has become an overt policy of Greece’s rightwing New Democracy government, which came to power last year. Interviews with five victims of pushbacks, 10 NGOs working across the Aegean Sea including Human Rights Watch, Josoor and the Aegean Boat Report, and a tranche of videos reviewed by the Guardian reveal an organised and systemic practice of denying entry to asylum seekers. Next week a coalition of charities including Human Rights Watch and the Border Violence Monitoring Network will publish an open letter condemning the practice of pushbacks and calling for the Greek government and the European Commission to take action against those involved. A draft of the letter seen by the Guardian calls for “disciplinary and criminal sanctions” to be brought against those “found to have engaged in such illegal acts”. International law experts say these activities are in breach of international law including the convention relating to the status of refugees and the European convention on human rights. “What you are seeing is the illegal collective expulsion of refugees from Greek territory,” said Satvinder Juss, a professor of human rights and international refugee law at King’s College London. “It’s a catastrophe for human rights.” Often pushbacks involve teams of unidentified men in black uniforms who intercept boats of refugees that have arrived in Greek waters and forcibly return them to Turkish waters, either leaving them to drift after engines have been destroyed or in separate liferafts. In some cases, victims have arrived on Greek land before being returned by authorities to the open seas, after actively threatening them with beatings, gunshots and by creating large waves with fast boats. In one case, refugees were left on a tiny island between Greece and Turkey for two days without food before being rescued. AlarmPhone, an NGO that operates a telephone line and social media network for refugees in distress, said it observed a substantial increase in reports of pushbacks since the pandemic, recording 55 cases between March and August. The Greek Helsinki Monitor said it submitted a report to the supreme court, naval court and military appeals court of Greece claiming nearly 1,400 people were pushed back between March and July, though the true number is believed to be far higher. Minos Mouzourakis, legal officer at Refugee Support Aegean, is currently working on landmark legal cases at the European court of human rights that date back to 2014, when eight Afghan children and three women died after their vessel sank near the island of Farmakonisi during a reported pushback. “This is a regrettable resurgence of those older tactics,” said Mouzourakis. In December 2019, Greece said it was predicting up to 100,000 asylum seekers to arrive on its islands from Turkey in 2020. But as of 31 August, there have been 8,860 sea arrivals, according to UNHCR. Stella Nanou, the agency’s Greek representative, acknowledged the “credible accounts” of pushbacks and called on Greece to “guarantee and safeguard the rights of those seeking international protection”. Kyriakos Mitsotakis, the Greek prime minister, has taken several official steps to ensure fewer refugees arrive, temporarily suspending the right to asylum, shortening the deadline for appeal in asylum cases, extending fences along the land border with Turkey and is considering installing floating barriers at sea. But the government has described accusations of illegal pushbacks as “fake news” from unreliable sources. “Pushbacks are inherently violent, not only physically but mentally,” said Amelia Cooper, advocacy and communications officer for Lesbos Legal Centre, which is documenting pushbacks and providing legal support to survivors. “Survivors are aware that these expulsions, and the abuses that they entail, are constitutive of both the European border and the EU’s political context with Turkey.” When contacted, the ministry of maritime affairs and insular policy said its operations were in accordance with international law and that the agency has been subject to “systematic targeting by a portion of the mainstream media, NGOs and other social networking platforms, which tend to promote the relevant actions in a single dimensional and fragmentary way”. But documents seen by the Guardian reveal a German navy supply vessel called the Berlin, which heads Nato’s Standing Maritime Group 2 in the Aegean region, observed a boat with refugees being forced into Turkish sea territory by Greek authorities on 19 June and 15 August. The findings came in response to parliamentary questions by Left party MP Andrej Hunko. After being detained in Turkey, Ahmed was released and has since slept in a park in the city of İzmir. “I don’t care if I die,” he said. “I don’t have a choice to go back. But I am losing hope.”