French President Emmanuel Macron on Thursday announced that his country would organize an international aid conference for Lebanon following the deadly explosions that rocked the Port of Beirut on Tuesday killing at least 137 and injuring over 5,000 others.

Macron made the remarks in Beirut, as he traveled to Lebanon in a show of solidarity.

Speaking to journalists, the French leader said the aid conference would be held "in the coming days."

He added that the funds raised from the conference would be challenged directly to the people ad relief organizations working on the ground.

Following the deadly blasts, various countries have moved fast to offer material support to Lebanon, including the deployment of various medical and emergency teams from foreign nations.

The blast rocked the Port of Beirut at around 6 p.m. local time (1610 GMT) Tuesday, shaking buildings all over the city and causing massive casualties and damages.

The cause of the blast is being investigated, but Lebanon's Prime Minister Hassan Diab said the cause of the massive explosion was 2,750 tonnes of ammonium nitrate stored in a warehouse for six years. President Michel Aoun tweeted it was "unacceptable" the explosives had been stored unsafely.

Macron called for an international investigation into the blast. "An international, open and transparent probe is needed to prevent things from remaining hidden and doubt from creeping in," he told reporters at the end of a snap visit to the Lebanese capital.

He added French investigators were on their way to Beirut.

Macron said he proposed to the Lebanese authorities a roadmap of urgent reforms to unlock billions of dollars in funds from the international community, and that he would return to Lebanon in September to follow up. 

"If reforms are not carried out, Lebanon will continue to sink," Macron said. "What is also needed here is political change. This explosion should be the start of a new era."

He told reporters that an audit was needed on the Lebanese central bank, among other urgent changes, and that the World Bank and United Nations would play a role in any Lebanese reforms. Talks with the IMF on a rescue package have stalled over the failure of the government to enact serious reforms. 

During his visit Macron met all Lebanese political factions and toured Beirut's shattered streets.

"I see the emotion on your face, the sadness, the pain. This is why I'm here," he told one group, shaking their hands on roads strewn with rubble and flanked by shops with windows blown out after Tuesday's blast.

After visiting a pharmacy damaged by the explosion, Macron told the crowd: "I understand your anger. I am not here to write a blank check ... to the regime."

(With input from agencies)