Watch: Huge explosions rock Lebanon's Beirut; buildings & cars totalled

A massive explosion rocked Beirut on Tuesday, flattening much of the city's port, damaging buildings across the capital and sending a giant mushroom cloud into the sky.

More than 70 people were killed and 3,000 injured, with bodies buried in the rubble, officials said.

It was not clear what caused the blast, which struck with the force of a 3.5 magnitude earthquake, according to Germany’s geosciences center GFZ, and was heard and felt as far away as Cyprus more than 200 kilometers (180 miles) across the Mediterranean.

Lebanon's interior minister said it appeared that a large cache of ammonium nitrate in the port had detonated.

For hours after the explosion, the most destructive in all of Lebanon’s troubled history, ambulances rushed in from around the country to carry away the wounded.

Hospitals quickly filled beyond capacity, pleading for blood supplies, and generators to keep their lights on.