United Nations Deputy Secretary General Asha-Rose Migiro visited the wounded on Sunday from a bomb blast at the UN headquarters in Nigeria that killed at least 23 people and injured dozens.
There has been no confirmed claim of responsibility for Friday's car bomb at the UN Abuja office, which blew out windows, gutted a lower floor and set the building alight in one of the most lethal attacks on the world body in its history.
A UN spokesman accompanying Migiro at the hospital where the victims were being treated said the death toll had risen.
"I can confirm to you that the casualty figure is now 23. This figure was given to us by the hospital authorities when they briefed us," he told Reuters.
President Goodluck Jonathan declined on Saturday, when visiting the site, to say who could be behind the blast, but security sources suspect the violent Islamist sect Boko Haram, which has been blamed for almost daily bomb and gun attacks on security forces and civilians in the remote northeast.