ISTANBUL- Turkey's central bank raised the highest of the four interest rates it uses to set policy by a less-than-expected 50 basis points on Thursday, its first rate hike in eight months after inflation hit a 14-year peak last month.The bank lifted its late liquidity window to 12.75 percent from 12.25 percent. It left the benchmark repo rate at 8 percent while the overnight lending rate was kept at 9.25 percent and the overnight borrowing rate at 7.25 percent.Seventeen of 18 economists in a Reuters poll had predicted a late liquidity window rate hike, with the average forecast being for a rise of 100 basis points. Six economists forecast a 25-100 basis point hike in the overnight lending rate."A tight stance in monetary policy will be maintained decisively until inflation outlook displays a significant improvement and becomes consistent with the targets," the bank said in its monetary policy committee statement, which was little changed from the previous statement.The lira TRYTOM=D3 weakened as far as 3.8913 after the announcement from around 3.8275 beforehand.While the central bank fights inflation pressures, President Tayyip Erdogan makes frequent calls for cheaper credit to boost the economy. The bank's resistance to lifting the repo rate has triggered concern among investors over the extent of its independence in the face of criticism from Erdogan.Turkey's economy has rebounded strongly from a downturn that followed an attempted coup last year, helped by a series of government stimulus measures. Gross domestic product surged 11.1 percent year on year in the third quarter, its fastest expansion in six years, data showed on Monday. urn:newsml:reuters.com:*:nL8N1OB0T6(Writing by Daren Butler; editing by John Stonestreet) ((daren.butler@tr.com; +90-212-350 7053; Reuters Messaging: daren.butler.thomsonreuters.com@reuters.net))