The step-grandmother of former President Barack Obama has died at the age of 99, family members in Kenya told the Associated Press.

Sarah Obama, affectionately known by family members as Mama Sarah, was the second wife of the former president's grandfather Hussein Onyango Obama, helped raise his father and has been close with him since he was a child. 

“The passing away of Mama Sarah is a big blow to our nation. We’ve lost a strong, virtuous woman, a matriarch who held together the Obama family and was an icon of family values,” President Uhuru Kenyatta told CNN.

“She was a philanthropist who mobilized funds to pay school fees for the orphans,” he added.

The United Nations honored her in 2014 with a Women’s Entrepreneurship Day Education Pioneer Award to commemorate her longstanding work with orphans in Kenya. 

According to The Associated Press, Sarah passed away at 4 a.m. on Monday at the Jaramogi Oginga Odinga Teaching and Referral hospital in Kisumu, Kenya's third-largest city.

"Mama was sick with normal diseases she did not die of COVID-19,” a family spokesman Sheik Musa Ismail told The Associated Press, with her daughter Marsat Onyango adding, "She died this morning. We are devastated.”

Ismail noted that she had been tested for COVID-19 and the test came back negative, but she had beens sick for about a week before succumbing to her illness. 

Her funeral will be held on Tuesday and Barack has been notified about her death. 

As President Kenyatta noted, she was well known in her village of Kogelo for her extensive work in education with orphans. Kisumu Governor Anyang Nyong’o told the Associated Press that he sent his condolences to the village, which is mourning the loss of the local leader. 

“She was a philanthropist who mobilized funds to pay school fees for the orphans,” he told The Associated Press.

Barack wrote about Sarah in his book Dreams from My Father, explaining that he met her as a small child and struggled to connect with her because of the language barrier. But throughout his life the two have become close and she attended his first inauguration in 2009. 

He mourned her in a Monday morning Facebook post, sharing her impact on their family.

For decades, Sarah had served as an integral figure in the community, helping to raise orphans in her own home and eventually through The Mama Sara Obama Foundation. 

She helped to provide for children who had lost their parents, giving them clothing, school materials and more.

In an interview with The Associated Press, she said she used to take Barack's father to school on her bike every morning and fought for everyone in her family to get an education because she never had one. 

She was particularly focused on women's education, noting that it was important for children to learn to be self-sufficient. She said she struggled to even read letters that were sent to her because she was not able to get an education. 

"I love education. If a woman gets an education she will not only educate her family but educate the entire village,” she said.

Africa News reported that Barack has sent his condolences to his family members in Kenya. 

"Just lost the most important person in my life – my gran, Mama Sarah. My heart is broken! But as I write, not able to stop the tears from pouring, I know I was blessed to have her for so long! My inspiration, my rock, my comfort zone, my safe space. Rest in peace Dani!" Barack's half sister Auma said on Twitter.