BERLIN -- German Chancellor Angela Merkel said Monday she had the "very highest respect" for German-born Pope Benedict XVI's decision to step down -- a move that the pontiff's brother said he had been considering for months amid ailing health.

Georg Ratzinger, 89, told the dpa news agency at his home in Regensburg that his brother had been advised by his doctor not to take any more transatlantic trips and was having increasing difficulty walking.

"His age is weighing on him," Ratzinger said of his 85-year-old brother, Pope Benedict XVI who announced earlier in the day he would resign Feb. 28. "At this age my brother wants more rest."

Ratzinger did not answer repeated calls to his home seeking further comment.

In Berlin, Merkel told reporters that she saw the pope's decision as one that he made for his church and its members.

"If the pope himself has now, after thorough consideration, come to the conclusion that he no longer has sufficient strength to exercise his office, that earns my very highest respect," she said. "In our time of ever-lengthening life, many people will be able to understand how the pope as well has to deal with the burdens of aging."

"As chancellor, I thank Benedict XVI for his work and wish him from the bottom of my heart all the best for the coming years," she said.

Merkel, who is a Protestant, praised Benedict for his efforts to promote dialogue with other Christian denominations and religions. She said that he "reached out his hand to Jews as well as Muslims."

"Benedict XVI is and will remain one of the most important religious thinkers of our time," she said.