Turkish inflation surged 17.9% year-on-year in August, official data showed today, hitting its highest level in nearly a decade and a half and underscoring the volatile outlook for prices amid a worsening currency crisis. 

Turkey's lira weakened immediately after the release of the data, the highest annual reading since late 2003. 

Inflation jumped 2.3% from the previous month, the data from the Turkish Statistical Institute showed, higher than the 2.23% forecast in a Reuters poll. 

The lira has fallen some 40% so far this year, hit by deepening concerns about President Tayyip Erdogan's control over monetary policy and a diplomatic rift with the US. 

That has driven up the prices of everything of food to fuel. 

For investors, the key question is whether the central bank will hike interest rates at its next policy-setting meeting on September 13. 

It left rates on hold at its last meeting in July, confounding expectations and sending the lira sharply weaker. 

Erdogan, a self-described "enemy of interest rates", wants to see lower borrowing costs to keep credit-fuelled growth on track. 

Investors, who fear the economy is set for a hard landing, want to see decisive interest rate increases.