US Secretary of State John Kerry has arrived in Lebanon, where he will pledge more aid to help Syria's neighbours deal with an influx of refugees and press Lebanese parliamentarians to swiftly choose a new president.
Lebanon has been unable to agree on a consensus candidate for president, creating a political vacuum at a time when the country is struggling to contain domestic sectarian violence while also grappling with a flood of Syrian refugees and declining economic growth.
"It is an important period now to show support for the Lebanese government," a senior State Department official told reporters.
The State Department said Kerry - whose visit to Lebanon came unannounced - will pledge more than $290m in additional aid for UN agencies and non-governmental organisations working with the nearly 3 million Syrian refugees in Lebanon, Jordan, Turkey, Iraq and Egypt.
Some $51m of the funds, the largest chunk of the aid, will go to helping Lebanon, which now hosts the highest concentration of refugees as a percentage of population in the world.
The influx has burdened public services and been a drag on the economy. Unlike some of Syria's other neighbours, Lebanon does not have formal refugee camps, leaving many families to find refuge within host communities.
More than $35m of the additional funds will go to helping refugees in Jordan, $15m to Turkey and the same amount to Iraq, while $4.5m will support Egypt, the State Department said.
'Lebanon needs president'
Lebanon has been without a president since May 25 when Michel Suleiman's six-year term expired. Attempts by politicians to pick a successor have foundered on longstanding rifts exacerbated by tensions over the Syrian war.
The presidency, allocated to the Maronite Christian community under Lebanon's sectarian division of power, is one of the three main political offices alongside the prime minister - a Sunni Muslim, and the parliamentary speaker - a Shia.
The war in Syria has split Lebanon's Christians just as it has divided Muslims. Shias mostly support Syrian President Bashar al-Assad and Sunnis mainly back the rebels.
Regional powers Saudi Arabia and Iran, whose endorsement is crucial to any political deal in Lebanon, are also in opposing camps over Syria.
The senior State Department official, speaking on condition of anonymity, said Kerry will press Lebanese politicians to elect a president as soon as possible.
"You need a fully empowered president to do everything that Lebanon needs to govern its territory and also to get the assistance from the international community that it really needs," the official said.
"While there is not a president, he wants to go in and express the desire to get that president elected," the official added.