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

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.

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.

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.

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."

Loading

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.

Get our Morning&Evening Edition newsletters

The most important news,analysis and insights delivered to your inbox at the start and end of each day. Sign up toThe Sydney Morning Herald’s newsletter here,toThe Age’s newsletter here and Brisbane Times' here.

Most Viewed in World

Loading