The funeral of Prince Rainier of Monaco will take place on April 15, the government in the principality announced.

Rainier died at the age of 81 after a month in hospital with severe breathing and heart problems.

The funeral is to take place in Monaco's 19th century cathedral at midday and be broadcast on television screens at the six other churches in the principality.

"Several high-ranking foreign and local personalities are to attend," the official statement said.

After the service, his body will be interred in the crypt next to his wife, the US actress Grace Kelly, who died in a car crash in 1982.

"It will be a simple funeral in accordance with the prince's wishes, similar to the one for Princess Grace," said Monaco Archbishop Bernard Barsi.

"Officials" will be able to pay their respects to his body lying in state at the palace chapel Monday, with Tuesday and Wednesday set aside for Monaco residents.

The government said Monaco had declared a three-month mourning period through July 6 for members of the royal family and household -- half that accorded to Princess Grace -- while the period for civil servants will be one month.

Casinos throughout the tiny Mediterranean territory closed for 24 hours following the early morning announcement of his death and will close again the day of the funeral, as will public institutions including schools.

The ministry said private establishments were invited to follow suit.