Petro and Colombia's first Lady Veronica Alcocer arrived at the central military hospital in Bogota on Saturday morning. They gave gifts to the children and talked to doctors and relatives about the children's health.
The siblings were found on Friday (June 9) in Caqueta province after weeks of searching by the military, indigenous communities and others, and were initially treated by military medics before being transported to a military hospital in the capital Bogota.
Four Indigenous children are in an "acceptable" state of health, the government said on Saturday.
"In general, the boy and the girls are in an acceptable state. According to the medical reports, they are out of danger," Defence Minister Ivan Velasquez said during a press conference after the visit.
The children are not yet able to eat, he added, but are being hydrated and stabilized.
The siblings have suffered insect bites and other minor injuries, army Mayor General Carlos Rincon said, but "life-threatening conditions are ruled out."
In photos shared by Colombia's military, the children appear gaunt.
The grandparents of the four children found alive in southern Colombia erupted in cheers after news of the rescue came through.
Fidencio Valencia, the grandfather of the three girls and one boy, told reporters he was delighted at the news of their rescue.
Grandfather Narcizo Mucutuy asked President Petro to transfer the children to Villavicencio to be reunited with their families after 40 days of searching.
Their ordeal began in the early hours of May 1, when the Cessna 206 aircraft carrying seven people and travelling between Araracuara airport in Caqueta and San Jose del Guaviare, a city in Guaviare province, issued a Mayday alert due to engine failure.
Three adults, including the pilot and the children's mother, died in the crash, and their bodies were found inside the plane.
The four siblings, aged 13, 9, and 4, as well as a now 12-month-old baby, survived the impact.
Aeroplanes and helicopters from Colombia's army and air force participated in the rescue operations.
Rescuers, supported by search dogs, had previously found discarded fruit the children ate to survive, as well as improvised shelters made with jungle vegetation.
Clues as to the siblings' whereabouts have been reported for weeks as the search, dubbed Operation Hope, continued.
Wilson, one of the military dogs which participated in the operation, is now himself missing, but an effort to find him is taking place, the military has said.
Reuters