An explosion sent shockwaves throughout Lebanon, killing at least 50 people and injuring more than 2,000.

On Tuesday evening, a huge explosion ripped through the Lebanese capital's waterfront, killing at least 50 people while injuring thousands of others, says Health Minster Hamad Hassan. And those numbers are expected to rise.

The Washington Post writes that the "cause of the late afternoon blast was not immediately clear, but senior officials said it appeared that flammable materials store in a warehouse had caught fire" and that an "earlier, smaller explosion had apparently ignited a fire, then came two secondary blasts." Those blasts created a massive mushroom cloud of flames and smoke over Beirut.

It's being said that the shockwaves could be heard and felt as far as Cyprus, which is hundreds of miles away.

"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," a witness told Reuters.

The US Embassy in Beirut urges people to "stay indoors and wear masks if available" due to reports of toxic gases being released from the blast.

Major General Abbas Ibrahim, head of Lebanon's general security service, said there were "highly explosive materials" stored at the blast site, according to Lebanon's National News Agency. 

While there are indications that the explosion was an accident, there are some "suspicions" that Israel may be involved. A senior Lebanese army officer said, "There will be no conclusion until there has been a full investigation." However, others have dismissed that belief completely, claiming that there was "no truth" to the reports of an Israeli strike at the port.

No definitive conclusion has been made yet.

*This is an ongoing story and will be updated with more information as it's released.