Nelson Mandela remained in critical condition on Monday, after his condition deteriorated in hospital over the weekend.

"The doctors are doing everything possible to ensure his well-being and comfort," President Jacob Zuma told a news conference on Monday.

Zuma and African National Congress Deputy President Cyril Ramaphosa visited the anti-apartheid icon at the Pretoria hospital on Sunday and were briefed on his condition by the medical team. They asked the world to pray for the 94-year-old former president and his family "during this difficult time".

A portrait of former South African President Nelson Mandela rests against the wall as messages written by visitors are seen on the wall at Regina Mundi church in Soweto township, a flashpoint during the anti-apartheid struggle, in Johannesburg, South Africa, on Sunday.

Mandela, who has been in the hospital with a lung infection since June 8, had been in "serious but stable" condition but was downgraded over the weekend, officials said.

In Washington, the White House National Security Council spokeswoman noted the latest reports from the South African government about the Nobel Peace Prize laureate's worsening condition.

"Our thoughts and prayers are with him, his family and the people of South Africa," spokeswoman Caitlin Hayden said.

In the statement, Zuma addressed reports that the ambulance that took Mandela to the hospital earlier this month broke down on the way, saying that the delay did not compromise his health.

"There were seven doctors in the convoy who were in full control of the situation throughout the period. He had expert medical care," his statement said.

"The fully equipped military ICU ambulance had a full complement of specialist medical staff including intensive care specialists and ICU nurses. The doctors also dismissed the media reports that Madiba suffered cardiac arrest. There is no truth at all in that report."

【新闻快讯】

南非总统府23日晚发布消息说，曼德拉的病情出现恶化。南非总统祖马当晚到比勒陀利亚的医院探视了曼德拉，并与曼德拉的夫人商讨了他的病情。南非总统祖马24日在记者会上表示，曼德拉的病情依然危急。南非人能做的，是为他祈福，希望他转危为安。 

曼德拉本月8日凌晨因肺部严重感染住院。这是他今年以来第三次入院接受治疗。

曼德拉病情转危的消息传出，极大地震动了南非社会。南非民众的心头普遍蒙上了一层悲伤的情绪。在收治曼德拉的比勒陀利亚医院外，围墙上贴满了祝福曼德拉平安康复的字条和图画。有的民众特意赶来，在医院的大门外摆上一束束鲜花。

曼德拉的病情也引发了国际社会的高度关注。美国白宫人士24日表态称，“将为曼德拉和他的家人祈祷”。美国总统奥巴马本周末即将访问南非，届时，奥巴马会否到医院探望曼德拉，尚不知晓。

曼德拉被视作南非反种族隔离斗士，曾在南非罗本岛监狱服刑27年。1993年，他和南非种族隔离政权的最后一名总统德克勒克共获诺贝尔和平奖。1994年，曼德拉当选南非第一位黑人总统，5年后卸任。下月18日曼德拉将迎来95岁生日。