The European Commissioner for Crisis Management Janez Lenarčič has announced a European Commission plan to deploy over 100 emergency personnel to Lebanon to help in the search and rescue operations in Beirut.

The capital was hit by a massive blast on Tuesday, killing at least 113 people and injuring more than 4,000 others.

Videos of the deadly blast went viral on social media, showing a cloud of smoke engulfing the port region of the city.

"We share the shock and sadness of the people of Beirut following the deadly explosion that has taken many lives and left many more injured. Our condolences go to all those that have lost loved ones," said Lenarčič.

"The EU Civil Protection Mechanism is now coordinating the urgent deployment of over a 100 highly trained firefighters, with vehicles, dogs and equipment, specialised in search and rescue in urban contexts."

The cause of the blast is being investigated, but Lebanon's prime minister, Hassan Diab, said the cause of the explosion was 2,700 tonnes of ammonium nitrate stored in a warehouse for six years. President Michel Aoun tweeted it was "unacceptable" the explosives had been stored unsafely. Aoun declared three days of mourning and called for a two-week state of emergency.