Japan's core consumer prices rose 0.8 percent in August from a year earlier, marking the third straight month of gains and the fastest increase in nearly five years, government data showed on Friday, suggesting steady progress towards ending 15 years of deflation.

The rise in the core consumer price index, which includes oil products but excludes volatile prices of fresh food, compared with a median forecast by economists for a 0.7 percent increase, the Internal Affairs Ministry data showed.

It followed a 0.7 percent increase in July and rose at the fastest pace since November 2008, when it rose 1 percent.

The so-called core-core inflation index, which excludes food and energy prices and is similar to the core index used in the United States, fell 0.1 percent in August compared with a year earlier.

Core consumer prices in Tokyo, available a month before the nationwide data, rose 0.2 percent in September from a year earlier, slightly less than a market forecast for a 0.3 percent increase.