International aid has been pouring into Lebanon a day after a massive explosion devastated Beirut's port on Tuesday, killing at least 100 people and wounding thousands.

The Chinese Foreign Ministry said the country is willing to provide assistance within its capacity and sent China's deep and sincere condolences to the victims, the injured and the families of the victims, according spokesperson Wang Wenbin at a press conference on Wednesday. 

Russia's emergency officials also said the country will send five planeloads of aid and will send rescuers, medical workers, a makeshift hospital and a lab for coronavirus testing to Lebanon.

France said it is sending two planes with dozens of emergency workers, a mobile medical unit and 15 tons of aid. French President Emmanuel Macron's office said the aid should allow for the treatment of some 500 victims.

French peacekeepers stationed in Lebanon, a former French protectorate, have been helping since the explosions, Macron's office said.

Jordan said a military field hospital including all necessary personnel will be dispatched, according to the Royal Court. Egypt has opened a field hospital in Beirut to receive the wounded.

Iran's President Hassan Rouhani also said Wednesday they have offered condolences and medical support to Lebanon after a huge blast at Beirut port devastated entire neighborhoods in the city.

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.

Czech Interior Minister Jan Hamacek said Lebanon has accepted an offer to send a team of 37 rescuers with sniffer dogs to Beirut. While Denmark said it is ready to provide humanitarian assistance to Lebanon, and Greece says it is ready to help Lebanese authorities "with all means at its disposal."

Lebanese Prime Minister Hassan Diab, in a short televised speech, appealed to all countries and friends of Lebanon to extend help to the small nation, saying: "We are witnessing a real catastrophe." He reiterated his pledge that those responsible for the massive explosion at Beirut's port will pay the price, without commenting on the cause.

Smoke was still rising from the port Wednesday morning. Major downtown streets were littered with debris and damaged vehicles, and building facades were blown out.

Lebanese Red Cross official George Kettaneh said at least 100 people were killed and more than 4,000 were wounded, and said the toll could rise further.

(With input from agencies)