Tit-for-tat expulsions

As violence escalated in Syria, the Assad regime declared 17 foreign diplomats as persona non grata in retaliation for the coordinated expulsion of Syrian diplomats from Western states following international outrage over the massacre in the Syrian town of Houla. In the UK three envoys, including the chargé d’affaires, were expelled.
In response, envoys from the UK, US, Switzerland, France, Italy, Spain, Belgium, Bulgaria, Germany, Canada and Turkey were asked to leave Syria.