US President Donald Trump and French President Emmanuel Macron on Friday discussed working together with other countries to send immediate aid to Lebanon, the White House said.
The two leaders spoke by phone and "expressed their deep sadness over the loss of life and devastation in Beirut," White House spokesman Judd Deere said in a statement.
Tuesday's massive explosion in Beirut's port killed 154 people, injured 5,000 and smashed a swathe of the city.
France and other countries around the world have rushed emergency aid to Lebanon, including doctors, and tons of health equipment and food.
Trump said this week Washington stood ready to help.
Washington has pledged over $17 million in initial disaster aid, the US embassy said on Friday.
It said in a statement that the aid included food assistance, medical supplies and financial assistance for the Lebanese Red Cross. “Announcements of additional aid and assistance are forthcoming,” it added.
On Thursday, Macron visited Beirut and assured angry crowds that aid to rebuild the city would not go to "corrupt hands".
Macron said France would lead international efforts to provide aid but would not give “blank checks to a system that no longer has the trust of its people.”
The cause of the blast remains under investigation.
Lebanese President Michel Aoun said on Friday said the probe would examine whether it was caused by a bomb, a prospect first raised publicly by Trump on Tuesday, hours after the blast.
Asked about the issue again on Wednesday, Trump said nobody could say for certain whether the explosion could have been caused by an attack.