A donor videoconference organised by France and the UN to provide aid for the devastated Lebanese capital of Beirut will be held on Sunday, the French president's office said on Saturday.
President Donald Trump said on Friday that the US would take part and that "everyone wants to help".
"We will be having a conference call on Sunday with President Macron, leaders of Lebanon and leaders from various other parts of the world," Mr Trump said.
The blast on Tuesday at Beirut's port killed more than 150 people and left as much as half the city heavily damaged.
Officials said tonnes of ammonium nitrate, a base compound for fertilisers and explosives, had languished for years in a warehouse at the port and caught fire, resulting in the explosion.
Arab League Chief Ahmed Aboul Gheit said on Saturday that he would seek to mobilise Arab efforts to provide support to Lebanon.
Speaking after a meeting with Lebanese President Michel Aoun, he said that the Cairo-based league was ready to assist an investigation.
"We are ready to help with all our means," he said.
Turkey was ready to help rebuild, Vice-President Fuat Oktay said during a visit to Lebanon on Saturday.
Turkey's port of Mersin, on the Mediterranean, was ready to assist the destroyed port of Beirut, he said, without elaborating.
Beirut has received a stream of international assistance since Tuesday.
On Friday, relief flights from Iran, Saudi Arabia and the UAE landed in Lebanon, following others from France, Kuwait, Qatar and Russia.
International police agency Interpol said it will send a team of victim identification specialists.
The World Health Organisation, meanwhile, called for $15 million (Dh55.1m) to cover immediate health needs.
Lebanon's hospitals, strained by rising coronavirus cases and economic crisis, were heavily damaged by the blast and overwhelmed by casualties.
Two days after the explosion, Lebanese were flocking to a 20-tent Russian field hospital set up in the capital's largest sports stadium.
The UN said up to 100,000 children were among the 300,000 people made homeless, including many who were separated from their families.
With destruction from the blast engulfing half of the capital and estimated to cost more than $10 billion, world leaders, advocacy groups and Lebanese have demanded an international investigation to ensure impartiality.
But Lebanon's powerful Hezbollah movement said on Friday that the army should lead such a probe because it was "trusted" by all.
Hezbollah head Hassan Nasrallah denied accusations the Shiite party had been storing arms at the port, saying: "We have nothing in the port."
