Monaco officials say Crown Prince Albert has taken over regency of the Mediterranean city-state, in light of the failing health of his father, Prince Rainier.
The announcement Thursday comes two days after a health bulletin called the 81-year-old ruler's prognosis "extremely reserved."
Prince Rainier, Europe's longest-reigning monarch, was hospitalized three weeks ago for heart, lung and kidney problems.
He ascended to the throne in 1949. His Grimaldi family has ruled the tiny principality on the French Riviera since the 13th century.
The prince is widely credited with turning the city-state, of less than two square kilometers in area, into a fashionable and wealthy tourist resort. His wife, Hollywood film star Grace Kelly, died in a car crash in 1982.
The 47-year-old Albert is the eldest of the couple's three children.
Some information for this report provided by AFP and AP.