The health of Prince Rainier of Monaco has stabilised but doctors say they remain worried over his condition.
The prince has been in and out of hospital in recent months
The 81-year-old prince has been on a respirator in intensive care in a principality hospital since Tuesday.
He is suffering lung, cardiac and kidney problems, although doctors say the deterioration of the function of the organs has been halted.
Pope John Paul II - also in ill health - sent a blessing offering "warm wishes" to the prince on Saturday.
A health statement issued by the palace on Sunday said: "The state of health of [Prince Rainier] remains worrying."
It said he was conscious but being sedated, "which allows him to tolerate absolutely indispensable respiratory assistance".
The bulletin said the prognosis was "very reserved". It had used the words "extremely reserved" on Saturday.
The prince's family celebrated a private Mass in the palace chapel on Sunday while citizens prayed for him in services around the country.
Prince Rainier has had heart and respiratory problems for 10 years and has been in and out of hospital in recent months.
Prince Albert and Princess Caroline have been at the bedside
Rainier III, who acceded to the small principality's throne in 1949, is one of Europe's longest-reigning monarchs.
He went into hospital on 7 March and had appeared to be getting better, but his health took a turn for the worse at the start of the week.
His three children - Crown Prince Albert, 47, Princess Caroline, 48, and Princess Stephanie, 40 - have been at his bedside.
Prince Rainier made world headlines with his marriage to Hollywood star Grace Kelly in 1956 after meeting her at the Cannes film festival.
His advancing age and ill health have led him to delegate more and more responsibility to his son and heir, Prince Albert.