rivaled heritage: Nelson Mandela's daughter to NBC News: 'I can't stress enough what a fighter he is'

Ben Curtis / AP

Zindzi Mandela, right, receives a hug from an unidentified woman as she arrives Wednesday at the Pretoria hospital where he father is being treated.

By Marian Smith, Cheryll Simpson and F. Brinley Bruton, NBC News

PRETORIA - Nelson Mandela ?is not going to go anywhere anytime soon,? one of the anti-apartheid icon's daughters told NBC News in an exclusive interview on Thursday.

Speaking to Special Correspondent Charlayne Hunter-Gault, Zindzi Mandela said her father was "very comfortable" and "responding" as he battles a lung infection at a Pretoria hospital.

NBC's Keir Simmons shares the latest of the condition of the South African president.

?His whole legacy is about fighting,? she said. ?I can't stress enough what a fighter he is. He?s a strong man. He's about resilience.?

When asked whether the family would welcome a visit by President Barack Obama, who is due to visit South Africa this weekend, Mandela said she wasn't aware of any formal request but added that decision would be left with doctors treating the Nobel Peace Prize laureate.

She described Mandela's condition as "typical for a 94-year-old man whose health is frail."

"He is with us," Mandela added.

Meanwhile, Mandela's eldest daughter said he appeared to be able to hear family members.

Speaking to SABC radio, Makaziwe Mandela said: "I?won't lie, it doesn't look good. But as I say, if we speak to him, he responds and tries to open his eyes. He's still there. He might be waning off, but he's still there."

Other members of the former South African president's family thanked well-wishers around the world for their support.

President Barrack Obama has said in the last hour that his thoughts and prayers are with Nelson Mandela's family. They have been at the 94 year old's bedside in hospital in Pretoria this morning, where he is still in a critical condition. His granddaughter, though, did tell reporters awaiting news outside the hospital that he is "stable." ITV's Neil Connery reports.

?Sometimes it is very hard for all of us in the family,? said Swati Dlamini, one of Mandela?s 17 grandchildren. ?We just appreciate that he?s loved.?

Relatives collected flowers from outside the hospital on Thursday. A choir prayed and sang outside the building, as other?people arrived to deliver bouquets and messages of support for the 94-year-old. By late afternoon, a crowd of about 1,000 people had gathered nearby.

Earlier, one family member described Mandela's condition as "stable." However, presidential spokesman Mac?Maharaj told reporters that the condition remained "critical."

Mandela has already spent 20 days in the hospital, his fourth hospitalization in six months.?

Earlier, President Jacob Zuma canceled a trip to Mozambique?in an indication of heightened concern about Mandela,?who is?widely regarded as the father of the nation and?whose health deteriorated last weekend.

In a statement, Zuma said that Mandela was "much better" Thursday than he had been the previous night.

"The medical team continues to do a sterling job," he added.

NBC News' Rohit Kachroo and Reuters contributed to this report.