Smoke rises from an explosion site at the port of Beirut, Lebanon, Aug. 4, 2020. Photo: VCG

Rescuers worked through the night into Wednesday after two enormous explosions ripped through Beirut's port, killing at least 78 people and injuring thousands, as they wrecked buildings across the Lebanese capital.

The second blast sent an enormous orange fireball into the sky, immediately followed by a tornado-like shockwave that flattened the port and shattered windows across the city.

The explosions - which were heard in Nicosia, 240 kilometers away in Cyprus - were logged by seismologists, registering as the equivalent of a 3.3-magnitude earthquake.

Bloodied, dazed and wounded people stumbled among the debris, glass shards and burning buildings in central Beirut.

Around 4,000 people were hurt by the blasts, with injuries recorded right across the city.

Lebanon is already reeling from an economic crisis that has left more than half of the population in poverty. The situation has been worsened in recent months by coronavirus.

Lebanese Prime Minister Hassan Diab said 2,750 tons of the agricultural fertilizer ammonium nitrate that had been stored for years in a portside warehouse had blown up, sparking "a disaster in every sense of the word."

"What happened today will not pass without accountability," said Diab. "Those responsible for this catastrophe will pay the price."

General Security chief Abbas Ibrahim said the material had been confiscated years earlier and stored in the warehouse, just minutes from Beirut's shopping and nightlife districts.

A soldier at the port, where relatives of the missing scrambled for news of their loved ones, told AFP: "It's a catastrophe inside. There are corpses on the ground. Ambulances are still lifting the dead."

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 officers refused her entry.

"It was like an atomic bomb," said Makrouhie Yerganian, a retired schoolteacher in her mid-70s who has lived near the port for decades.

"I've experienced everything, but nothing like this before," she said.

AFP correspondents saw shop and apartment windows blown out and streets covered with broken glass.

Photos posted online showed damage to the inside of Beirut airport's terminal, nine kilometers from the explosion.

Hospitals already struggling with the country's coronavirus outbreak were overwhelmed by the influx of wounded people and the country's Red Cross called for urgent blood donations.

AFP