Opponents say President Recep Tayyip Erdogan manipulates the courts and the media to tighten his grip on power, and now is trying to prevent a top contender from running for president.

Turkish police have detained the strongest rival to President Recep Tayyip Erdogan, a move that experts say is aimed at removing all possible contenders ahead of the next presidential election and further stretching his rule.

The moves against Istanbul Mayor Ekrem Imamoglu and dozens of others could help extend President Recep Tayyip Erdogan’s two decades in power.