At least 73 dead and thousands injured after massive explosion rocks Beirut

Data collected by the United States Geological Survey shows that the massive explosion in Beirut was so powerful, it created seismic waves equivalent of a magnitude 3.3 earthquake.

However, the magnitude 3.3 equivalent isn't, "directly comparable to an earthquake of similar size."

That's because surface type blasts, like the Beirut explosion, don't produce as large a magnitude as an earthquake of similar energy would according to Don Blakeman, a geophysicist at the National Earthquake Information Center. Blakeman said most of the energy goes into the air and buildings.

"Not enough of the energy is transmitted into the rocks in the ground," he said.

Meaning, if the explosion had occurred below the surface of the earth, the magnitude would have registered even higher.

Ambulances drive past the site of the explosion. Hassan Ammar/AP

The death toll in the massive blast that shook Beirut has reached 73, the Lebanese national broadcaster TeleLiban reported citing Health Minister Hamad Hassan.

The minister said earlier today that at least 2,750 had been injured in the explosion.

People ride past a car destroyed after a building wall collapsed on August 4. Daniel Carde/Getty Images

The US Embassy in Beirut is urging those in the area of the explosion to “stay indoors and wear masks if available” due to reports of toxic gases released from the blast.

An embassy security alert went out following the explosion.

"There are reports of toxic gases released in the explosion so all in the area should stay indoors and wear masks if available," the embassy warned.

The embassy also urged US citizens in the affected areas to "contact their loved ones directly and/or update their status on social media."

Israel is offering humanitarian medical assistance to Lebanon following the massive blast in Beirut Tuesday afternoon, even though the two countries have no diplomatic relations.

“Under the direction of Minister of Defense, Benny Gantz, and Minister of Foreign Affairs, Gabi Ashkenazi, Israel approached Lebanon through international defense and diplomatic channels to offer the Lebanese government medical humanitarian aid,” a statement read.

Following the announcement, Israel’s President Reuven Rivlin tweeted, “We share the pain of the Lebanese people and sincerely reach out to offer our aid at this difficult time.”

Lebanon is one of a small number of countries Israel regards as an enemy state, and there have been no diplomatic relations since a ceasefire signed between the two countries in 1949.

As recently as last week, Prime Minister Benjamin Netanyahu was warning that Lebanon, along with Hezbollah, bore “full responsibility” for what the Israeli army described as an infiltration by a Hezbollah cell into Israeli territory.

A view of a damaged street and buildings caused by a massive explosion in Beirut's port. Marwan Naamani/dpa/Alamy Live News

The aid agency Save the Children warned of children unaccounted for after a deadly explosion in Beirut that "wiped out entire streets," according to a statement from the organization.

"We are shocked and devastated by the explosion today. The death toll may not be known for several days but what we do know is that in a disaster like this, children may be hurt, shocked, and separated from their parents," said Jad Sakr, the organization's director in Lebanon.

"It is vital that children and their families get access to the services they urgently need, including medical care and physical and emotional protection," Sakr added.

The organization also reported that hospitals are "completely overwhelmed" and "unable to treat further casualties as hundreds of beds immediately filled up following the blast." The agency described the explosion "as the biggest explosion in Lebanon's recent history."

Save the Children's offices in Beirut were also badly damaged by the explosion.

Nina dos Santos

Photos taken from inside the Grand Serail, the government palace and the headquarters of Lebanon’s prime minister, showed some damage inside the building.

The building is about 1 mile (1.6 kilometers) from the site of the explosion.

The blast also dealt considerable damage to the Baabda Palace, the official residence of the Lebanese president, according to Lebanese state media.

The United Nations Interim Force in Lebanon (UNIFIL) says some of its naval peacekeepers were injured — some seriously — by the explosion that rocked Beirut on Tuesday. 

A maritime task force ship was also damaged by the explosion. 

“We are with the people and the Government of Lebanon during this difficult time and stand ready to help and provide any assistance and support," the UNIFIL head of Mission and Force Commander Major General Stefano Del Col said.

Tele Liban/AFP

Lebanese Prime Minister Hassan Diab said that Tuesday’s explosion in the Lebanese capital “will not pass without accountability” and “those responsible will pay for what happened.”

He said that an investigation into the explosion will include “revelations that will be announced about this dangerous warehouse which has been present since 2014,” without providing any additional details.

Describing the explosion as a “catastrophe,” he said in a televised statement that the priority now was to recover the dead and treat the injured. 

He concluded by making “an emergency call to all those countries who love this country to stand by us and to help us heal our deep wounds.”

Hani Abughazaleh and friends had been fishing off the coast of Beirut, Lebanon.  

"We heard a couple of small explosions and saw white smoke rising above," he told CNN.  

CNN's producer in Beirut Ghazi Balkiz said the initial explosion happened at 6:07 p.m. local time.

Abughazaleh began taking a video at 6:08 p.m. local time and seven seconds later, the massive red explosion cloud appears. The sudden and intense explosion is so powerful a massive, visible shockwave forms in the sky.

Watch the moment:

He said when the shockwave hit the group, it almost knocked them off the boat.

"We saw a red plume rising and people panicked wondering if it's some sort of lethal gas," he said.

"Oh my God," someone in the video exclaims.

Two more videos taken by Abughazaleh shows the red cloud billowing above Beirut.  

As the boat began to make its way back to the shore along the coast, the red cloud appears to have dispersed and a red haze appears in the air.

"I drove home to asses the damage in my house and saw hundreds of injured people," he said.