Beirut, Lebanon (CNN)A massive explosion ripped through central Beirut on Tuesday, injuring hundreds of people and blowing out windows in buildings across the city.
The blast near the port in the Lebanese capital sent up a huge mushroom cloud-shaped shockwave, flipping over cars and damaging buildings miles away.
An "uncountable" number of people were wounded by the blast, the state-run National News Agency reported, and footage from the scene captured the injured staggering through streets in the capital. One eyewitness described the scenes as "like an apocalypse."
There were conflicting reports on what caused the explosion, which was initially blamed on a major fire at a warehouse for firecrackers near the port, according to NNA. The director of the general security directorate later said the blast was caused by confiscated "high explosive materials," but did not provide further details.
A red cloud hung over the city in the wake of the explosion as firefighting teams rushed to the scene to try to put out the fire. At least 10 firefighters were missing, according to the city's governor Marwan Abboud, who said the scene reminded him of "Hiroshima and Nagasaki."
"In my life I haven't seen destruction on this scale," Abboud said. "This is a national catastrophe."
Chaotic scenes filled Beirut's hospitals as doctors conducted triage on dozens of wounded people. Some had broken limbs, others had been showered with shards of glass. Some patients were unconscious.
One of Beirut's major hospitals, Hotel Dieu, received around 400 injured patients, an employee told CNN.
The blast damaged buildings across the city, including the official residence of Lebanon's president, the headquarters of former Prime Minister Saad Hariri, and CNN's bureau in downtown Beirut. Homes as far as 10 kilometers away were damaged, according to witnesses.
One Beirut resident who was several kilometers away from the site of the blast said her windows had been shattered by the explosion. "What I felt was that it was an earthquake," Rania Masri told CNN.
"The apartment shook horizontally and all of a sudden it felt like an explosion and the windows and doors burst open. The glass just broke. So many homes were damaged or destroyed."
Bachar Ghattas, an eyewitness, described scenes of chaos in Beirut on Tuesday evening: "You can see injured people all over the streets in Beirut, glass all over the place, cars are damaged, it is like an apocalypse."
"It is very, very frightening what is happening right now, and people are freaking out. The emergency services are overwhelmed," Ghattas told CNN. "Beirut port is totally destroyed."
The blast comes at a tense time in Lebanon. On Friday a UN-backed panel is expected to issue a verdict on the 2005 assassination of former prime minister Rafik Hariri, a move many fear will stoke sectarian tensions. The country is also in the midst of an economic meltdown, with ballooning unemployment, a tanking currency and poverty rates soaring above 50%.