TUNIS, April 25 (Reuters) - Tunisia central bank has decided to raise its key interest rate for the first time in three years after the dinar currency fell to historic lows against the euro, the bank's governor said on Tuesday.

Governor Chedli Ayari did not give the adjusted rate in the interview with state television, but the benchmark interest rate is now 4.25 percent. He said more details would be announced on Wednesday.

He said the bank on Tuesday injected $100 million into market to support the dinar, which fell to 2.53 dinars to the euro last week.

(Reporting by Tarek Amara; writing by Patrick Markey) ((pat.markey@thomsonreuters.com; +213-661-692993; Reuters Messaging: pat.markey.thomsonreuters.com@reuters.net))