Arrests and deportations of foreign teachers in China have soared this year, lawyers, schools and teachers say, amid a broad crackdown defined by new police tactics and Beijing's push for a "cleaner," more patriotic education system.

Four law firms told Reuters that requests for representation involving foreign teachers had surged in the past six months by between four and tenfold, while teachers and schools confirmed arrests and temporary detentions for minor crimes had become commonplace.

Switzerland-based Education First (EF), which runs 300 schools across 50 Chinese cities, has seen a "significant" increase in detentions in China for alleged offenses including drugs, fighting and cybersecurity violations, according to a June 27 internal notice sent to employees and seen by Reuters.