Hezbollah leader Sayyed Hassan Nasrallah said on Thursday his party was not happy with the prime minister's helping to fund a U.N.-backed court investigating the killing of statesman Rafik al-Hariri, but that it would not work against it.

Lebanon, facing international pressure, has now paid its more than $30-million (19 million pounds) share resolving months of political wrangling that threatened to bring down the government.

Prime Minister Najib Mikati had threatened to resign if he could not fund the Special Tribunal for Lebanon, which is investigating the 2005 bombing that killed former Prime Minister Rafik al-Hariri, and has indicted four Hezbollah members.

Hezbollah, a powerful Shi'ite political party and guerilla group backed by Iran and Syria, rejects what it labels as a politicised and conspiratorial court as biased in U.S. and Israeli interests.

But he said in his televised speech commemorating the Shi'ite Muslim holy day Ashoura that his party would not do anything to jeopardise stability in Lebanon.

We stress our firm rejection of the legality and constitutionality of funding the court or cooperating with it in any way, but we will not cause a problem in the country and we will serve the higher national interest, he said.

Nasrallah said Mikati had embarrassed himself by moving to fund the international investigation.

Mikati came to power in January with Hezbollah's support when the last government fell over disputes about the court. Hezbollah and its allies have the power to block measures in cabinet with half the seats, but Nasrallah softened his tone over the funding issue to avoid a public clash.

BACKDOOR COURT FUNDING

A Lebanese official told Reuters that in order to avert a cabinet vote but still allow funding to pass and preserve the government, politicians agreed to send the money through a government relief fund normally used for natural disasters or humanitarian aid.

Nasrallah, however, argued that the move was still unacceptable to Hezbollah because it was publicly funded.

We reject paying any money from the pockets of the Lebanese people to fund this court, he said.

Mikati, whose government had struggled to reach a deal on the funding, stressed the move was necessary to preserve Lebanon and prevent it from being exposed to any severe decisions.

The European Union, which provides Lebanon with about $50 million of aid annually, had not explicitly threatened to cut funding but repeatedly urged Beirut to pay up.

U.S. ambassador Maura Connelly, while praising Mikati's agreement to fund the court, added in a statement that Lebanon's commitments to the Tribunal extend beyond the issue of funding alone.

This appeared to refer to requests that Lebanon hand over the four Hezbollah suspects, who have not been tracked down since their indictment in July.

But Nasrallah on Thursday stressed his party's decision not to undermine Mikati's decision in no way reflected an indirect acceptance of the court, and said it had no intention of handing over the four Hezbollah suspects: The one has nothing to do with the other.

(Reporting by Erika Solomon and Laila Bassam; Editing by Jon Hemming)