PRETORIA, South Africa — South Africans maintained a vigil for Nelson Mandela, the nation’s first black president, who’s in critical condition in a Pretoria hospital where he has spent the past three weeks after contracting a lung infection.

Several hundred people flocked to the hospital Thursday night to wish Mandela well and deliver cards and flowers. Their ranks had thinned to about 100 Friday morning.

“We love Mandela,” said Sylvia Sikhosana, 28, a pre- primary teacher, who came to the hospital with three colleagues and about 12 children from their school. “We really want him to get better.”

Concern over Mandela’s health heightened after President Jacob Zuma canceled a trip to a regional summit in Mozambique late on June 26. Mandela’s condition improved overnight and was stable, though still critical, the presidency said Thursday.

Well-wishers have also gone to Mandela’s homes in Johannesburg and the village of Qunu in the southeast of the country, while the ruling African National Congress has staged prayer meetings.

“Our thoughts and prayers right now are with the people of South Africa,” President Barack Obama, who is scheduled to arrive in the country later Friday for an official visit, told reporters in Dakar, Senegal. Mandela is “a hero for the world. His legacy is one that will linger on throughout the ages.”

BIRTHDAY PLANS

Mandela, who is due to turn 95 next month, served a single five-year term as president after his ANC won the country’s first multiracial elections in 1994. He spent 27 years in jail for opposing white minority rule and won the Nobel Peace Prize in 1993.

“We love you Mandela,” five-year-old Thando Kual said in an interview outside the hospital. “We want you to get well because we want to celebrate your birthday with you.”

Doctors downgraded Mandela’s condition to critical on June 23.

Mandela continues to open his eyes and respond to touch, his daughter Makaziwe told the state-owned SAfm radio station Thursday.

“I can reiterate that Tata is very critical,” she said, using the Xhosa-language word for father. “Anything is imminent. It’s only God who knows when the time to go is.”