Iran's Rouhani offers aid to Lebanon after Beirut blast
Tehran "is ready to offer medical and medicinal aid and help treat the injured and other assistance," Rouhani wrote in a message to his Lebanese counterpart, according to the government website.
Rouhani also expressed hope the cause of the deadly blast would be uncovered and calm restored to Beirut as soon as possible.
The Lebanese Red Cross said on Wednesday that the blast killed over 100 people and injured more than 4,000, according to the latest toll.
The explosion appeared to have been sparked by a fire igniting 2,750 tonnes of ammonium nitrate left unsecured in a warehouse.
The head of Iran's Red Crescent Society said in a statement that it would send nine tonnes of food aid as well as medical supplies to Lebanon.
Karim Hemmati added that Iran would also provide Lebanon with a field hospital as well as specialised medical teams and equipment.
Lebanon's current government, which was unveiled in January, is made up of the pro-Iranian Shia movement Hezbollah and its allies.
France, the United States and Israel have offered assistance to Beirut following the tragedy.
Qatar said it would dispatch field hospitals to support victims of the blast.