If Lebanon is unable to produce its share of the funding for the Special Tribunal, we're going to have to take some pretty tough decisions, and I think you're going to see some consequences in terms of the US-Lebanese bilateral relationship," Assistant Secretary of State for Near Eastern Affairs Jeffrey Feltman said in an interview with Al-Arabiya television in Washington.
"I’d expect the same thing in terms of some other countries as well."
Lebanon is responsible for meeting 49 per cent of the costs of the UN-backed Special Tribunal for Lebanon (STL), which has charged four Hezbollah members in the 2005 assassination of billionaire ex-premier Hariri.
But the Hezbollah-dominated government has yet to pay its share, estimated at $35 million (25.2 million euros) for 2011, as international pressure mounts on Prime Minister Najib Mikati to uphold his commitment to the STL.
"Mr Mikati has said publicly ... that he is committed to meeting Lebanon’s obligations to the international community," said Feltman.
"One of those obligations is payment of the Lebanese contributions to the Special Tribunal for Lebanon."
Mikati in recent weeks has received a series of notifications from the court on the overdue funds.
Hezbollah leader Hassan Nasrallah, whose Shiite militant party is blacklisted as a terrorist group by Washington, has openly opposed Lebanon paying its annual share to the Netherlands-based STL.
Nasrallah has dismissed the court as a US-Israeli conspiracy against his Iranian-backed party, warning that no member of Hezbollah would ever be found or arrested.
In January, Hezbollah toppled Lebanon's Western-backed government, led by Hariri's son Saad, in a feud over the STL, ushering in telecommunications tycoon Mikati to replace him.
In 2010, the Hariri government transferred funds to the STL without cabinet approval.