The EU move came as France President Macron said that France will organise a conference in the next few days to raise money for food, medicine, housing and other urgent aid.
The European Union has released $39 million (33 million euros) to finance emergency aid for Lebanon and mobilised material resources, including an Italian hospital ship, to help relief efforts in Beirut after this week's devastating explosions.
A donor conference is also planned to mobilise additional funding for reconstruction after an assessment of what is required, said an EU source on Thursday.
The release of the $39 million should make it possible to cover the immediate needs of the emergency services and hospitals in the capital, said the European Commission.
Commission President Ursula von der Leyen spoke by phone with Lebanese Prime Minister Hassan Diab on Thursday to discuss European Union assistance.
In a letter to the 27 EU members released on Thursday evening, von der Leyen and Charles Michel, President of the European Council, called on member states to "contribute to the road to recovery that lies ahead".
"We... invite you to intensify your support to Lebanon both on the immediate needs, but also with a view to the longer-term reconstruction of the country," the leaders wrote.
"In order to ensure efficiency and swift delivery, we stand ready to ensure the synergy of the aid that you and the EU as a whole will provide to Lebanon, through a coordination mechanism that the EU institutions will put in place."
They reminded the 27 member states of the "strong partnership" between the EU and Lebanon, "a country of strategic importance which hosts the largest number of refugees per capita".
"We have a common interest in acting now to limit the fall-out of this tragedy," they said.
European countries have mobilised quickly with the Italian navy making available a ship with helicopter medical evacuation capability and a flight containing 8.5 tonnes of medical equipment.
"We are at the side of the Lebanese people and we will work in the coming days to give them the greatest possible support," said Italian Foreign Minister Luigi Di Maio on Thursday.
"What happened... is a tragedy that has struck the Lebanese people, and from our point of view helping a friendly country like Lebanon also means stopping a process of destabilisation and instability which risks having an effect on migration."
Di Maio said Italy had sent "firemen, soldiers, specialists... and eight tonnes of medical aid".
UN sends $9 million to address immediate needs
The United Nations says it is releasing $9 million to address immediate needs following the explosion that devastated Beirut and help strengthen operations in the city’s hospitals.
UN deputy spokesman Farhan Haq said the money from the Lebanese Humanitarian Fund will be following by additional funds from the UN’s Central Emergency Response Fund.
He said the UN is carrying out assessments of the damage and needs resulting from the massive explosion and hopes to hold a meeting on Monday to inform the 193 UN member states of the results and launch an appeal to help Lebanon.
He says: “We’re trying to get the relevant figures ready as soon as we can.”
Haq said the World Health Organization reported that the blast left three hospitals unusable and two others with substantial damage and that “the equivalent of 500 hospital beds have been lost."
He said the initial $9 million will be used to expand and establish additional intensive care units where needed and provide trauma kits, ventilators, medical supplies and medicine.
WHO will help “cover 1,000 trauma interventions and 1,000 surgical interventions for people suffering from burns and wounds caused by glass and other debris resulting from the blast.”
No blank check, Macron warns
During a trip to Beirut, French President Emmanuel Macron announced that France will organise a conference in the next few days with European, American, Middle Eastern and other donors to raise money for food, medicine, housing and other urgent aid.
But he warned Lebanon's political leadership that he wouldn’t give “blank checks to a system that no longer has the trust of its people.” He called on them to create a "new political order.”
He promised a “clear and transparent governance” so that the aid goes directly to the population and aid groups.
On the narrow street, a crowd gathered around Macron and shouted their anger, chanting, “Revolution!” and “The people want to bring down the regime!” — slogans used at mass protests last year.
Macron told them he would speak to Lebanon’s political leaders.
“I will propose to them a new political pact this afternoon,” he said. “I will be back on the first of September and if they can’t do it, I will keep my responsibility toward you.” He also promised that French aid would be given out with transparency and “will not go into the hands of corruption.”
US begins aid deliveries
The United States began delivering aid to Lebanon, amid longstanding concerns about how officials can ensure that supplies get to those in need, and not to the Iranian-backed Hezbollah.
The first C-17 transport aircraft with 11 pallets of food, water and medical supplies from the US military's Central Command arrived from Qatar and two more were expected in the next 24 hours.
US officials said the administration also plans to provide at least $15 million in disaster assistance. The officials were not authorised to discuss the matter ahead of a formal announcement and spoke on condition of anonymity.