Visiting Turkish Prime Minister Recep Tayyip Erdogan on Wednesday urged Lebanon's rival parties to unite and overcome a crisis linked to a UN probe into the assassination of the country's ex-premier.

"The premier stressed the importance of stability in Lebanon and the need for all parties to come together and find solutions to all matters related to the international tribunal," said a statement issued by the Lebanese presidency following a meeting between Erdogan and President Michel Sleiman.

Turkey would "work to help preserve the unity of Lebanon," Erdogan said after a meeting with Lebanese parliament speaker Nabih Berri.

Erdogan underlined the importance of avoiding a civil conflict that could spread through the region while meeting with Sleiman and Berri, a Lebanese government official said on condition of anonymity.

The Turkish premier's two-day visit comes amid a standoff between the camp of Prime Minister Saad Hariri and the powerful militant group Hezbollah over a UN-backed court probing the murder of Hariri's father, ex-premier Rafiq Hariri.

His arrival in Beirut was punctuated by a group of Armenians protesting what they say was genocide against their community by Turkey's precursor, the Ottoman Empire, in the early 20th century.

"The aim of (Erdogan's) visit was to sign bilateral agreements... and strengthen quadripartite ties among Turkey, Syria, Jordan and Lebanon," Sleiman's office said.

"The meeting also covered... the importance of finding solutions to all matters related to the international tribunal."

Tribunal

Erdogan's trip comes as Lebanon anxiously awaits an anticipated indictment by the Special Tribunal for Lebanon, which is investigating the 2005 bombing that killed Rafiq Hariri and 22 others.

Tensions are soaring in Beirut as the STL is reportedly set to implicate high-ranking Hezbollah operatives in the Hariri murder, a move the Shiite militant party has warned against.

Erdogan, whose country played a key role in mediating now-frozen peace talks between Syria and Israel, said Turkey would do everything in its power to prevent war in Lebanon, in comments published hours ahead of his visit.

"Should any signs of war surface in Lebanon, God forbid, Turkey and other countries in the region will do everything they can to prevent that war," Erdogan told the Lebanese daily As-Safir on the eve of his visit.

"Today we stand by Lebanon as we always have," he said.

Mediator

Turkey is widely seen as aiming to position itself as a central regional mediator in the troubled Middle East.

In the evening, Erdogan told a joint news conference with Hariri that he had contacted Syrian President Bashar al-Assad before his visit and would get in touch with him again on his return to Ankara to "evaluate the situation."

"Lebanon must be free of these pressures... we hope it finds stability," said the Turkish leader.

Hariri welcomed the comments and said that "dialogue is essential. We must give dialogue a priority."

He also reiterated the UN-backed tribunal was established under UN Security Council resolutions and "nobody can change that," in reference to Hezbollah's call for a boycott of the proceedings.

Hariri and Erdogan signed a free trade agreement between the two countries, after an agreement was reached earlier this year on establishing a free trade zone that also includes Jordan and Syria.

On Thursday, Erdogan is due to visit Turkish troops serving the UN peacekeeping force in southern Lebanon.

According to Lebanese political sources indictments against members of Shi'ite guerrilla group Hezbollah in the 2005 killing of Hariri are expected to be issued by the end of this year or in early 2011.