The confirmed death toll stood at 73 at 2:00 am but with more than 3,000 wounded and hospitals struggling to cope, a much higher final count seemed inevitable.
Members of the security forces broke down in tears when one of their colleagues was brought to them dead on a stretcher.
A fellow police officer pulled out a picture of the deceased with his fiancee, as his comrades wept.
An entire port engulfed in fire, ships ablaze at sea and crumbling buildings: the site of the massive blast in Beirut's harbour area resembled a post-nuclear landscape.
Soldiers cordoned off the area, littered with glass and debris from the explosion which officials said was the result of fire catching in a warehouse where hundreds of tonnes of ammonium nitrate were stored.
A woman in her twenties stood screaming at security forces, asking about the fate of her brother, a port employee.
"His name is Jad, his eyes are green," she pleaded, to no avail as security forces would not let her enter.
Nearby another woman almost fainted while also asking about her brother who worked at the port.
Ambulance sirens rang throughout the area as vehicles ferried the dead out for at least three hours and fire trucks rushed in and out of the blast zone.
Inside the port itself, the hangars looked like charred cans, everything destroyed beyond recognition as fire-fighting helicopters flew overhead, dumping water.
Abandoned luggage was strewn across the area. Next to one untouched bag lay an unattended corpse.
Every parked vehicle within a radius of several hundred metres sustained damage from blast, so big that it was felt in Cyprus, 240 kilometres (150 miles) away.
'Corpses everywhere'
The cars closest to the site of the explosion were reduced to scrapyard metal, their wailing alarms and flashing lights adding to the chaos.
Exhausted firemen were rushing to the scene, some searching for colleagues sent in earlier to put out the initial fire that was raging before the bigger explosion shook the city.
With the help of the security forces, civil defence teams scoured the area for corpses, as officers screamed at reporters who were trying to document the disaster.
"What are you taking pictures of? There are corpses everywhere," said one of them.
The confirmed death toll stood at 78 but with more than 3,000 wounded and hospitals struggling to cope, a much higher final count seemed inevitable.
Members of the security forces broke down in tears when one of their colleagues was brought to them dead on a stretcher.
A fellow police officer pulled out a picture of the deceased with his fiancee, as his comrades wept.
'Don't know what to do'
A ship anchored off the port was ablaze from the mushroom of fire, causing panic among the authorities fearing the fuel onboard would trigger another tragedy.
Sitting on a sidewalk near the site of the blast, at least 10 crew members of two cargo ships damaged in the explosion were waiting to be treated by medics.
"The ship is sinking in the water, the explosion caused an opening in it, and there are serious injuries on board," said an Egyptian member of the crew of one of the ships, Mero Star.
"We heard firecrackers and we saw smoke coming out of a warehouse ... and after a few minutes the explosion happened," said another crew member, who asked not be named.
Syrian and Egyptian crew had arrived at the port on Tuesday on board a ship carrying cargo from Ukraine, and many were planning to head back home on Tuesday.
"From the day we set sail six months ago, we had been looking forward to this day of homecoming," said one Syrian seafarer.
Another Egyptian crew member said he was planning to go back home on Wednesday after months at sea.
"But I will not be able to," he told AFP. "I don't know what to do."