(Adds annual inflation rate, context)
LIMA, Oct 1 (Reuters) - Peru's annual inflation rate slowed to 3.90 percent in September, when consumer prices rose just 0.03 percent, state statistics agency Inei said on Thursday.
Exchange rate pressures on prices let up in September after the central bank tightened controls on currency derivatives and raised the benchmark interest rate. The policies helped stop the sol's rapid depreciation against the dollar.
Inei said the cost of fuels and some foods also fell in September. Prices rose by 3.43 percent in the first nine months of the year.
The 0.03 percent reading for metropolitan Lima, which the central bank uses to guide monetary policy, was the smallest monthly rise in consumer prices since November. It came in well below the 0.23 percent increase forecast in a Reuters poll.
The central bank's target range for the annual inflation rate is between 1 percent and 3 percent.
The head of the central bank has said he expects inflation to cool to between 3.4 percent and 3.6 percent by the end of the year.
September August September 2014 Monthly rate +0.03 +0.38 +0.16 12-month rate +3.90 +4.04 +2.74 (Reporting by Teresa Cespedes Editing by W Simon and Lisa Von Ahn)