Iran’s double-digit inflation rate worsened for the sixth consecutive month in March, the government said on Monday, in what appeared to be an implicit acknowledgment that international sanctions linked to the disputed Iranian nuclear program are causing some economic harm.

The government’s statistics office said the rate increased in March to an annualized 31.5 percent, compared with 30.2 percent in February and 26.4 percent a year earlier, the semiofficial Mehr News Agency reported. The Mehr report did not offer an explanation for the increase except to specify that much of it was in the categories of food, beverages and tobacco.

Many economists say the real rate could be at least double the official rate, partly because it does not fully take into account the prices of many imported goods, which have become prohibitively expensive. The main reason is the severe depreciation of the rial, Iran’s national currency, as the sanctions that have limited Central Bank activities and oil exports have taken hold.

Some experts believe the Iranian inflation calculation deliberately understates the actual rate in order to present a public face of resistance to the coercive pressures inflicted by the sanctions, which have been imposed largely by the United States and European Union.