"I followed the smoke until I reached the port of Beirut," he told CNN Arabic, explaining that "professional intuition" took him to Al Roum hospital, in the Ashrafieh district. The area has been left devastated by the blast.

What he saw there was remarkable. "I was amazed when I saw the nurse holding three newborns," Jawich said. "I noticed the nurse's calm, which contrasted the surrounding atmosphere just one meter away." Several dead and injured people lay nearby, he said.

"However, the nurse looked like she possessed a hidden force that gave her self-control and the ability to save those children. People stand out amidst these violent and dark and evil circumstances and this nurse was up to the task," he said.

Jawich said the nurse told him later that evening that she was in the maternity ward when the blast hit. She said she had been knocked unconscious, and when she came around "found herself carrying these three children," he told CNN Arabic.

Not everyone in the hospital was so lucky. George Saad, emergency preparedness and disaster manager for the hospital, told CNN that 12 patients, two visitors and four nurses died in the incident yesterday, while two remain in critical condition. Some 80% of the hospital had been damaged, along with 50% of its equipment, he said.

Saad told CNN that the babies and their mothers have been transferred to other hospitals.

It's still not exactly clear what led to the explosion that wiped out entire streets across the seaside capital. The blast has been linked to a large supply of confiscated and potentially unsecured explosive material, stored in a warehouse at the city's port, close to populated areas.

As world leaders and international organizations offer assistance, local officials are also launching an investigation into the blast.

Beirut's hospitals were quickly inundated, with doctors conducting triage as dozens flooded into emergency rooms. The emergency section of one major hospital, the American University of Beirut Medical Center, reached capacity. Four other hospitals are out of service after sustaining damage in the explosion, according to Lebanon's health minister.

Mehsen Mekhtfe reported from Beirut, Ghazal Salah, Dareen al Omari and Caroline Faraj reported from Dubai and Amy Woodyatt wrote from London. Helen Regan, Tamara Qiblawi, Ghazi Balkiz and Ben Wedeman contributed reporting.