Hundreds of Chinese foreign exchange students were subjected to harassment and interrogation at American airports as they were leaving the country this summer, Beijing said on Wednesday. “For some time the United States has been using judicial power to wantonly harass and interrogate Chinese students, and even arrest and prosecute them under false allegations,” foreign ministry spokesman Zhao Lijian told a press conference. Between May and September, nearly 300 students “experienced harassment and interrogation”, he said. Several of them had their “cell phones, laptops and other personal belongings were arbitrarily examined and even seized”. The official did not give details of any specific cases or say how the figure had been calculated, but the allegation comes amid a slump in relations between Beijing and Washington that has led to Chinese students visiting and working in America coming under much tighter scrutiny. Several senior US officials, including President Donald Trump and Secretary of State Mike Pompeo, have warned of the threat of Chinese students and academics spying for Beijing. Last month, two Americans pleaded guilty at a court in Washington to using fake passports and other counterfeit documents to help Chinese nationals acquire student visas. In July, the US Department of Justice arrested four Chinese academics for lying about their ties to the Chinese military on their visa applications, while in June, three Chinese students were sentenced to up to a year in prison for taking pictures of a US naval base in Florida. In 2018, the US justice department launched a programme to monitor illegal activity by Chinese nationals in America. It subsequently claimed that about 60 per cent of all cases involving the theft of trade secrets had some connection to China. Trump’s national security adviser Robert O’Brien said this week that the government was working with universities to protect the rights of Chinese exchange students, but also to counter the influence of the Chinese Communist Party on American campuses. “Chinese students, coming here to learn rather than to steal, are always welcome,” he said in an article published in Foreign Affairs magazine on Tuesday. Earlier this month, Pompeo and US Secretary of Education Betsy DeVos sent a letter to university leaders saying the Chinese government may be monitoring both American and Chinese students on their campuses. Last month, deputy national security adviser Matt Pottinger said the US was taking a “surgical approach” to its monitoring of potential spies, targeting just 1 per cent of the 400,000 Chinese students studying in the US. Australian writer detained in Beijing told supporter he was a former Chinese spy Despite the uneasy relations between the two countries, the United States remains the most popular destination for Chinese foreign exchange students, followed by Britain , Australia and Canada, according to a report by market research firm New Oriental. A study by Georgetown University last week said Chinese nationals accounted for 16 per cent of all foreign undergraduates studying STEM subjects – science, technology, engineering and mathematics – in the US.