International students are turning away from the United States and Britain in favour of universities in Asia and continental Europe, a global university survey showed ​on Thursday, as tighter visa rules redraw the global map of higher ‌education. International students typically pay far higher fees than domestic ones and are a major source of revenue, helping offset their host countries' teaching and research costs. Britain and the US recorded the steepest drops in international undergraduate ​numbers, down 19% and 13%, respectively, in the October-August period compared with the ​same period a year earlier, the survey of 437 universities in 63 countries ⁠conducted by Studyportals, NAFSA and Oxford Test of English showed. Canada and Australia also saw ​weaker demand, while universities in Asia and Europe reported stronger international enrolment growth, they said. Studyportals ​is a Netherlands-based student recruitment platform, NAFSA is a US-based nonprofit that advocates for international education, and the Oxford Test of English is run by Oxford University Press. US institutions were the most pessimistic about the outlook, ​with more than a third expecting enrolments to decline further in the coming years. Read More: Visa scam exposed at Islamabad airport The survey ​found that visa restrictions and government policies were the biggest barriers to recruitment, with processing delays, tougher ‌screening and ⁠changes to post-study work rules prompting students to defer or abandon plans to enrol. The decline in interest in US universities comes after President Donald Trump tightened scrutiny of international students, expanding social media checks, revoking thousands of visas and imposing tougher rules on how long they can ​stay in the country. ​The survey was conducted ⁠before the November 3 midterm elections in which Democrats won control of both chambers of Congress, although the president retains executive authority over ​visa rules. Meanwhile, Britain has tightened its student visa rules as successive ​governments seek to ⁠reduce immigration, restricting most international students from bringing dependants and planning to shorten the period graduates can remain in the country to work or seek employment. "These survey results affirm what we've observed ⁠before: ​national policies matter to international students making major decisions about ​where to study, conduct research, or start a career," Dr Fanta Aw, the executive director and CEO of NAFSA, ​said.