WASHINGTON (AP) — President Barack Obama is sending his thanks and prayers to Pope Benedict XVI, who announced Monday that he will step down this month.

Obama says he and first lady Michelle Obama have warm memories of their 2009 visit with the pope. Obama is offering best wishes to the cardinals who will gather in mid-March to choose his successor, and says Catholics play a key role in the U.S. and abroad.

Benedict became the first pontiff to step down in 600 years when he declared he would resign Feb. 28, citing a lack of strength to do the job. When he was elected in 2005, he was 78 — the oldest pope chosen in nearly 300 years.