Hospitals overwhelmed as explosion rocks Lebanese capital Beirut

London: The federal government is trying to confirm whether more Australians have been killed or injured in the massive explosion that rocked the city of Beirut, with shockwaves being felt in Cyprus nearly 250km away.

Lebanon's Prime Minister Hassan Diab, in a short televised speech, has appealed to all countries and friends of Lebanon to extend help to the small nation, saying: “We are witnessing a real catastrophe.” He reiterated his pledge that those responsible for the massive explosion at Beirut’s port will pay the price, without commenting on the cause.

The US President Donald Trump has claimed the explosion was an attack. But Australian security agencies on Wednesday night were saying there was no evidence the explosion was deliberate.

Foreign Minister Marise Payne said it was a "devastating explosion" and "very, very confronting".

At least 100 people were killed, including one Australian, and 4000 wounded in the explosion on Tuesday night local time, Lebanon's health minister Hamad Hasan said. Up to 20,000 Australians reside in Beirut and the federal government is working with Lebanese authorities to confirm further fatalities or injuries.

"Tragically we have lost one Australian, we are not going into the details of that at the moment while we work with family and consular authorities while we support them," Senator Payne told 2GB's Ben Fordham.

"The size of this event, the size of the explosion and its impact, is going to have caused a very significant number of fatalities."

The explosion took place at 6:07pm on Tuesday local time near Beirut's port and central district, close to many highly-populated areas and tourist sites. Extraordinary footage shows a fire was raging at a large warehouse in the port district when something triggered a huge blast which sent a pink-coloured mushroom cloud towering above the city. The blast was felt in Cyprus, around 250 kilometres (150 miles) away, and registered as a 3.3 magnitude earthquake.

Authorities said the blast was linked to 2750 tons of ammonium nitrate stored in a port warehouse, It's still unclear what exactly caused the explosion. But a number of experts believe military munitions and propellants were present as well as the ammonium nitrate.

Ammonium nitrate, a compound of ammonia and nitrogen, is a highly volatile material used in agricultural fertilisers and bombs.

The Lebanese Health Ministry said hospitals were overwhelmed by an influx of casualties. The Lebanese Red Cross said hospitals in the city were either so full or so badly damaged that hundreds of patients have had to be turned away or treated on the street or in car parks.

Major General Abbas Ibrahim, the head of Lebanon's General Security Directorate, said the ammonium nitrate had been seized from a ship and kept in a warehouse at the port, causing disbelief that such a dangerous substance could be stored in the densely populated capital. It may have been there for up to six years.

"It appears that there is a warehouse containing material that was confiscated years ago, and it appears that it was highly explosive material," he said.

Prime Minister Scott Morrison said one Australian had been killed in the blast and embassy staff were working to determine how many others had been injured.

"I can confirm there has been one Australian that has been killed," Morrison said on Wednesday morning.

"Which is terribly devastating and, obviously, we can't give more details about the specifics at this time but our sympathies to all of the people in Lebanon.

"There is such a large Lebanese Australian community here and they would be worried about loved ones. The details will hopefully be provided soon."

A number of staff members at the Australian embassy have received glass injuries from the smashed windows, but no employee is believed to be seriously injured.

It is understood that an Australian consular team was travelling to Beirut to assist the local team with any Australian casualties.

Beirut Governor Marwan Abboud said the capital was a disaster area, with the damage "enormous".

“This reminds me of what happened in Japan, to Hiroshima and Nagasaki,” he said.

“I’ve never seen damage of this size and width and so catastrophic. This is a national catastrophe. This is a problem for Lebanon, and we don’t know how we’re going to get out of it."

Lebanese President Michel Aoun said in a Twitter post it was "unacceptable" that so much ammonium nitrate could have been stored in central Beirut for so long. He also declared a two-week state of emergency.

An injured man walks at the explosion scene that hit the seaport, in Beirut.Credit: AP

The Lebanese Red Cross has issued an urgent call for blood and was bringing ambulances from elsewhere in the country into Beirut to help.

Lebanon’s Prime Minister, Hassan Diab, declared Wednesday a national day of mourning for the victims.

In a televised speech, he said he would soon "reveal facts" about the warehouse where the explosion occurred and suggested there may have been issues with the site for several years.

"I promise you this catastrophe will not pass without accountability. The people who are responsible will pay a price," he said.

The force of the explosion flipped cars on the roofs. Credit: AP

Amal Saad, a political science professor at the Lebanese University, tweeted: "No words can describe what I just saw at the hospital ER."

"I rushed there because of severe pain in my left arm and swelling. We couldn’t get to the entrance because of the pile of corpses that hadn’t been moved. The dozens of severely injured people, including migrant workers. No words."

At a White House press conference on Tuesday (Wednesday AEST) Trump said the explosion "looks like a terrible attack".

Asked if he was confident if the explosion was an attack rather than an accident, Trump said: "It would seem like it based on the explosion.

Civilians carry a person at the explosion scene that hit the seaport.Credit: AP

"I've met with some of our great generals and they just seem to feel that it was not a...some kind of manufacturing explosion type of event."

He said the generals "seem to think it was an attack".

"It was a bomb of some kind," he said.

But the Australian government has seen no evidence the explosion was deliberate, with senior government sources saying it appeared it was an accident.

Smoke rises in the aftermath of a massive explosion in Beirut.Credit: AP

British Prime Minister Boris Johnson said the images coming out of Lebanon were "shocking".

"All of my thoughts and prayers are with those caught up in this terrible incident. The UK is ready to provide support in any way we can, including to those British nationals affected."

Local television footage showed severe damage to several houses and shops across the city, including the home of former prime minister Saad Hariri.

Debris filled the ground at the port and other footage showed damaged container trucks and vehicles.

"I saw a fireball and smoke billowing over Beirut. People were screaming and running, bleeding. Balconies were blown off buildings. Glass in high-rise buildings shattered and fell to the street," one witness told Reuters.

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