A statement from Samaritano hospital signed by his doctor Fernando Gjorup said Niemeyer was "lucid and continues to receive physiotherapy in the coronary unit", but there was no sign of significant improvement.

Niemeyer, the winner of the 1988 Pritzker prize, is best known as one of the main designers of Brasilia, the futuristic capital built in 1960.

A pioneer in the use of reinforced concrete to produce soaring, curvaceous forms, he has designed 600 works around the world and has some 20 other projects underway.

The architect, who will turn 105 on December 15, was hospitalized on November 2 suffering from dehydration after coming down with the flu, the latest in a series of lengthening hospital stays.

His only daughter, Anna Maria Niemeyer, died of emphysema in June at age 82.