Vietnamese inflation slowed to its weakest pace in eight months in May, official data showed Friday, in the latest sign that the economy is cooling.

Consumer prices rose 6.36 percent year-on-year in May, the Government Statistics Office said, slightly down from a 6.61 percent increase reported in April.

Economists attribute the slowdown in inflation to past monetary policy tightening and an easing of demand from domestic consumers.

"There is a big risk of inflation pressure and unstable macro-economic developments," the government said Monday, in a report to the country's National Assembly.

In 2011, Vietnam repeatedly raised interest rates to prevent the economy from overheating and to rein in double-digit inflation, but with the economy weakening the authorities last year resumed stimulus efforts.

Vietnam cut interest rates in May for the eighth time in little more than a year, in a bid to spur bank lending and boost consumption after economic growth fell to a 13-year low of 5.03 percent in 2012.

The country's GDP in the first quarter of the year grew by 4.89 percent from a year earlier, below expectations and prompting the government to admit there were many "shortcomings and weakness" in the economy.