By Hernan Nessi

BUENOS AIRES (Reuters) - Argentina's annual inflation rate ended 2023 at 211.4%, the highest since the early 1990s, official data showed on Thursday, propeling the embattled South American country's year rise in prices above Venezuela for the first time in decades.

Argentina's monthly inflation also hit 25.5% in December, below forecasts, after a sharp devaluation of the local peso by the new government of libertarian President Javier Milei, who came into office last month pledging to fix the economic crisis.

The inflation data, the first involving a period since Milei took office on Dec. 10, underscores the huge challenge his government faces, despite sealing a key agreement with the International Monetary Fund (IMF) this week. Milei has warned of hyperinflation without major reforms to stall prices.

Argentina's regional peer Venezuela, long the Latin American country with the highest inflation rate, has seen prices cool in recent months, with its annual 2023 inflation rate estimated around 193% after out-of-control hyperinflation in recent years.