To pressure President Recep Tayyip Erdogan over the jailing of his top rival, the opposition wants Turks to boycott companies that back Mr. Erdogan and plans to organize a protest this weekend.

Ekrem Imamoglu, the mayor of Istanbul and a popular figure, had boasted jokingly that he was the only person to have beaten Recep Tayyip Erdogan’s ruling party in three local elections.

Turkish authorities detained a lawyer for President Tayyip Erdogan's biggest political rival, jailed Istanbul Mayor Ekrem Imamoglu, an MP of the main opposition party, CHP, said on Friday. Imamoglu, a CHP member who leads Erdoguan in some polls,