Sarah Obama, step-grandmother to former President Obama, dies at 99 in Kenya

March 29 (UPI) -- Sarah Obama, the step-grandmother of former President Barack Obama, died in Kenya on Monday. She was 99.

The Standard newspaper in Kenya reported that Obama died while undergoing treatment at Jaramogi Oginga Odinga Teaching and Referral Hospital in Kisumu. Relatives did not disclose the cause of death.

Kisumu is about 170 miles northwest of the capital Nairobi.

Kenyan President Uhuru Kenyatta acknowledged her death in a statement.

"The passing away of Mama Sarah is a big blow to our nation," he said. "We've lost a strong, virtuous woman. A matriarch who held together the Obama family and was an icon of family values."

The second wife of the former president's paternal grandfather, Hussein Obama, Sarah Obama helped raise Barack Obama Sr., the father to the 44th U.S. president.

In his memoir Dreams From My Father, President Obama referred to his step grandmother as "granny." She was also known to friends as "Mama Sarah."

The former president first met Sarah Obama during a trip to Kenya in 1988 and had to communicate through interpreters, as she only spoke Luo. Two decades later, she would attend his first inauguration in 2009.

"My family and I are mourning the loss of our beloved grandmother, Sarah Ogwel Onyango Obama, affectionately known to many as 'Mama Sarah' but known to us as 'Dani' or 'Granny,'" the former president tweeted Monday, with a photo of the two during the 1988 trip.

"We will miss her dearly, but we'll celebrate with gratitude her long and remarkable life."

Kenyatta said Sarah Obama will be remembered for her philanthropic work, especially in her hometown village of Nyang'oma-Kogelo in Siaya County.

Sarah Obama founded The Mama Sarah Obama Foundation to help educate children in her native Kenya. For her efforts, she received the inaugural Women's Entrepreneurship Day Education Pioneer Award at the United Nations in 2014.