But USA Today, quoting Spain's Telecino TV, reported the 86-year-old former pope is "in a very bad way."
Cardinal Joachim Meisner, the archbishop of Cologne, Germany, and a friend of Benedict's, visited the former pope in April.
"I was shocked at how thin he had become," Meisner, 79, said at the time. "Mentally, he is quite fit, his old self. But he had halved in size."
A Vatican spokesman, the Rev. Federico Lombardi, acknowledges Benedict has weakened since stepping down Feb. 28, but he denies Benedict's physical condition is critical.
"He is old and his strength is slowly ebbing," Lombardi said last month. "However, there is no special illness. He is an old man who is healthy."
Benedict -- the first pope to resign since Gregory XII quit in 1415 and the first to do so on his own initiative since Celestine V in 1294 -- announced his resignation to the full college of cardinals Feb. 11, citing a "lack of strength of mind and body" due to his advanced age.
He told an assembly of priests Feb. 14 that after retirement he would "remain hidden to the world," leading a cloistered "life of prayer."
He lives in the Mater Ecclesiae monastery in the Vatican Gardens near St. Peter's Basilica. The monastery was formerly home to 12 nuns.
With him are his personal secretary, Monsignor Georg Gaenswein, a 56-year-old German archbishop, and four consecrated women, who look after him, preparing his meals and tending to the household.