ANKARA, March 25 - Turkey's foreign ministry summoned Switzerland's deputy ambassador to Ankara on Saturday over a protest in the Swiss capital Bern against President Tayyip Erdogan, the state-run Anadolu agency reported, Anadolu said some 250 people, including supporters of the outlawed Kurdistan Workers Party (PKK), staged a rally earlier on Saturday in Bern calling for a 'No' vote in an April referendum in Turkey that could give Erdogan sweeping new powers. The PKK is designated a terrorist organization by Turkey, the United States and the European Union.