Chaotic scenes in Beirut hospital

A CNN producer in Beirut has described the "chaotic scene," in the emergency room of one Beirut's hospitals, with doctors conducting triage as they try to treat dozens of people injured in Tuesday's explosion.

"Some people had broken limbs, some showered with glass," Ghazi Balkiz said. 

"I walked in, I saw a few people lying on the floor -- doctors trying to put IVs into them. A couple of people were passed out," he added. 

Footage shared on social media captured the explosion as it rocked Beirut.

One video, filmed from a nearby boat, appears to show a white pall of smoke rising over the city. Seconds later, a red plume of smoke can be seen shooting into the sky, followed by a massive explosion.

The second video, shared on Instagram, shows the explosion as seen from a rooftop in the capital.

A wounded man walks near the scene of an explosion. Anwar Amro/AFP/Getty Images

Lebanese authorities say an explosion near Beirut's port on Tuesday evening has left a large number of people injured, CNN's Senior Correspondent Ben Wedeman reports.

The explosion caused massive damage to the surrounding area and sent a huge cloud of red smoke over the city.

Lebanon's state-run NNA news agency reports that a major fire broke out near Beirut port and firefighting teams have rushed to the scene to put out the fire.

The Lebanese Red Cross is calling on its medics to mobilize immediately, and report to their respective centers, to help deal with the massive explosion that rocked Beirut port on Tuesday evening, it said on Twitter. 

Red Cross teams are trying to reach the site of the blast, it added. 

Smoke rises in Beirut. Mohamed Azakir/Reuters

A red cloud hung over Beirut in the wake of the blast, as firefighting teams rushed to the scene to try to put out the fire.

Homes up to 10 kilometers (6 miles) away were damaged, according to witnesses, and footage from local media showed wrecked cars, apparently flipped over by the force of the blast.

One Beirut resident who was several kilometers away from the site of the explosion said her windows had been shattered by the explosion. "What I felt was that it was an earthquake," Rania Masri told CNN.

The huge explosion in Lebanon's capital, Beirut, blew out the windows of the CNN bureau, according to CNN's correspondent Ben Wedeman, who said he saw a cloud of red smoke drift over the city after the blast.

Wedeman said he had "never felt anything like it ... [I've] been around the block and seen pretty large explosions ... and this was bigger," he told CNN's Becky Anderson, adding that he only heard and felt one explosion.

"As far as I can tell there was just one absolutely massive explosion which caused all this damage in the Lebanese capital."

Lebanon's state-run NNA news reports that a major fire broke out in a warehouse used for storing firecrackers, near Beirut's port, and strong explosions were heard shortly afterwards.

Wedeman said the cause of the blast was "still not clear -- if it was fireworks, as some news sources are saying -- they are some damn big fireworks."

Watch CNN's Ben Wedeman from the scene:

An explosion is seen in Beirut, Lebanon, on August 4. Anwar Amro/AFP/Getty Images

A large explosion rocked the Lebanese capital Beirut on Tuesday, damaging buildings and offices around the city. 

Lebanon's state-run NNA news reports that a major fire broke out in a warehouse used for storing firecrackers, near Beirut's port, and strong explosions were heard shortly afterwards.

Firefighting teams have rushed to the scene and are working to put out the fire.