IRNA � Supreme Leader Ayatollah Seyyed Ali Khamenei in a Twitter message late on Wednesday expressed solidarity with the Lebanese people over the massive fatal blast in Beirut on Tuesday night.

"We sympathize with the dear Lebanese citizens and stand by them in the painful tragedy of the explosion in the port of Beirut, which killed and injured a large number of people and caused severe damage. Patience in the face of this incident will be a golden page in Lebanon honors," Ayatollah Khamenei said.

A massive explosion rocked the Lebanese capital of Beirut leaving a very high number of casualties.

A warehouse at the Beirut Port caught fire on Tuesday afternoon, triggering a huge explosion, Lebanon�s official National News Agency (NNA) reported.

Several smaller explosions were heard before the bigger one occurred.

Abbas Ibrahim, the head of Lebanon�s General Security, said that �highly explosive materials� ammonium nitrate confiscated earlier had been stored at the site.

Footage shared on the social media captured the moment of the bigger explosion, with columns of thick smoke billowing fast across several hundreds of meters and shrouding the area.

The tragedy has so far claimed at least 100 lives and injured over 4,000 people.