WASHINGTON (AFP) - Former US president George W. Bush has become a grandfather following the birth of his daughter Jenna's first child, a girl named Margaret Laura "Mila" Hager.

"Laura and I are thrilled to announce the birth of our grandchild," Mr Bush, who was president from 2001-2009, announced on Facebook on Sunday, saying the baby was born the night before at 8.43pm in New York City (8.43am Singapore time on Monday).

"Mila, daughter of Jenna and Henry Hager, is named for her grandmothers...

We met our beautiful granddaughter today. Jenna and Mila are healthy. And our family is elated."

Ms Jenna Bush Hager, 31, one of Bush's twin daughters, announced the pregnancy in December on NBC's Today show, where she has worked as a correspondent since 2009. The show posted a series of baby pictures on its website.