Nelson Mandela's daughter says he is 'very critical' A man looks at tributes outside the Mediclinic Heart hospital in Pretoria on June 27, 2013, where former South African Nelson Mandela is on life support. NELSON Mandela was in a "very critical" condition on life support, his daughter said, adding "anything is imminent" for the revered anti-apartheid hero. "Tata (father) is very critical," daughter Makaziwe Mandela told state radio SAFM. Anything is imminent, but I want to emphasise again that it is only God who knows when the time to go is. I won't lie. It doesn't look good," she said. But "if we speak to him he responds and tries to open his eyes - he's still there." His granddaugter Ndileka Mandela said Mandela's family were taking comfort from messages of support from the public, the BBC reported in a tweet. Clan elder Napilisi Mandela told AFP that the former South African president "is using machines to breathe." "It is bad, but what can we do," said Napilisi Mandela, who usually presides over family rituals and meetings. South Africans praying for 94-year-old Nelson Mandela say they are also preparing to bid him goodbye after an announcement his health has deteriorated yet again. Jessica Gray reports. US President Barack Obama said that Mandela was a "hero for the world" whose legacy will live on throughout the ages. He is a personal hero. I think he is a hero for the world, and if and when he passes from this place, one thing I think we all know is that his legacy is one that will linger on throughout the ages," Obama said in Senegal. Obama said Mandela had inspired him to become involved in politics and insisted he was still planning to travel to South Africa, and said the prayers of the American people were with the South African ex-president's family. Obama, using Mandela's clan name "Madiba," said Mandela had given him a "sense of what is possible in the world, when righteous people of goodwill work together." The Salvation Army has lead prayers and hymns outside the hospital today where 94-year-old Mandela remains. It comes as South Africans brace themselves for the worst today after the country's President Jacob Zuma cancelled a trip out of the country. Zuma's spokesman Mac Maharaj said that Mr Mandela's condition had deteriorated over the weekend and after consultations with doctors, the president cancelled his trip to a regional summit in the Mozambican capital Maputo. South African president Jacob Zuma has cancelled an overseas trip amid growing concerns for Nelson Mandela. Mdileka Mandela visited her grandfather in hospital and picked up flowers left by the growing crowds. "He's stable and we'd like to say that we thank everybody for giving their support and praying with us ... we are anxious as you know that he is critical but he's in a stable condition right now," Mdileka said. It's been hard, especially because of all of this - that we have to do everything in the public eye. Mandela - or Madiba as he is known - is now on life support on his 20th day in hospital. The Salvation Army's chief secretary for South Africa Robert Donaldson lead a prayer for Mandela as officers sang a hymn. You have the future in your hands. You have the future of this nation in your hands and you have the future of the leader of this nation in your hands ... bring grace to our former President and all his family. Bless them and encourage them Lord, at this difficult time," he prayed. Members of the Salvation Army sang the hymn, "In thee o Lord do I put my trust" after laying some flowers at the hospital gates. Salvation Army's territorial commander William Langa had a message for the ailing anti-apartheid leader: "Lift up your head, look up to God and be encouraged." Mr Langa said the group had come to pay respects and to support Mandela as his health fails him and the nation now fears his end is near. We know it is very difficult and it is a challenging time for the country and for the world. Madiba is a symbolic icon," Mr Langa said. Nelson Mandela 'very critical' Source: AFP Well wishers continue to come to the gates of the Mediclinic Heart Hospital in Pretoria to lay flowers, cards and balloons and to give support and love to the man who lead the nation from the dark days of apartheid after 27 years in jail. Released from jail in 1990 he saw the shackles of apartheid lifted and was elected President in 1994. He became a symbol of peace, reconciliation and forgiveness in South Africa as he called for the so-called Rainbow Nation to forgive the past and live together in harmony. His health is now failing just short of his 95th birthday as he battles a lung infection. He is now on life support. A family stands outside the Mediclinic Heart hospital in Pretoria on June 27, 2013, where former South African Nelson Mandela is on life support. In a sign of how parlous his condition has become, the country's President Jacob Zuma visited Mandela's hospital late last night and emerged to say that he was still critical. President Zuma then cancelled a planned visit to Mozambique today in a sign that the inevitable bad news may come soon. His family, including wife Graca Michel, remain at his bedside. Mandela's failing health comes as US President Barack Obama is due in South Africa on a long planned visit tomorrow. People look at tributes outside the Mediclinic Heart hospital in Pretoria on June 27, 2013, where former South African Nelson Mandela is on life support. Well wishers have placed cards and balloons and messages of support on the hospital fence. My beloved Madiba, thank you for sacrificing your life to give me and my son a brighter future in our beloved country after too many years of darkness ... It is time to rest," one note said.