Palestinian president Mahmud Abbas is due in Beirut Wednesday, where he is expected to offer the Lebanese authorities assurances that the Palestinian refugee camps will stay clear of the country's growing Syria-related unrest.
During his three-day visit, Abbas is also expected to discuss the situation of Palestinians who fled Syria for Lebanon, which is already home to some 470,000 Palestinian refugees living in 12 official camps.
Abbas is slated to meet with Lebanese President Michel Sleiman soon after his arrival mid-afternoon.
Abbas will reassure the Lebanese authorities "of our firm and unwavering commitment to stability and security in Lebanon, and to the neutrality of the Palestinian camps" in Lebanon's unrest, embassy spokesman Hassan Sheshniyeh said.
The main topic on Abbas' agenda for his Beirut visit is "security", including that of the Palestinian camps, researcher Michel Naufal told AFP.
Abbas will insist "on the principle that the Palestinians are not a card that any (of Lebanon's political movements) can use", said Naufal, of Beirut's Institute for Palestine Studies.
The visit comes a week after a fierce battle pitting radical Sunnis loyal to Sheikh Ahmad al-Assir against the Lebanese army raged in the southern city of Sidon, in which 18 troops were killed.
Nearby, clashes broke out pitting the army against Islamist fighters on the edges of Palestinian Ain al-Helweh camp, Lebanon's largest.
Within hours, the violence there subsided thanks to the intervention of Abbas and the chief of the Hamas Islamist group which runs the Gaza Strip, Khaled Meshaal.
Abbas "wants to offer his guarantees to Lebanese officials over the situation in the camps, after the situation in Sidon was successfully brought under control", added Naufal.
He also "aims to ensure that attempts by some sides to drag (the Palestinians) to intervene on Assir's side are not repeated", said the researcher.
The main groups in Lebanon's impoverished camps are Abbas' Fatah, its main competitor Hamas, the Islamic Jihad and several other Islamist groups.
Barring Nahr al-Bared in the north, all camps are off-limits to the Lebanese army and security forces, turning some of them into a refuge for fugitives.
Assir gained prominence in Lebanon over his virulent anti-Hezbollah discourse.
The powerful Lebanese Shiite movement is a close ally of the Syrian regime of President Bashar al-Assad, and its fighters are engaged in the war, causing deep resentment among Lebanon's Sunnis.
The conflict has meanwhile forced more than 500,000 Syrians to flee into Lebanon, the UN says.
An additional 65,000 Palestinians who resided in Syria have also fled into Lebanon, many of them taking refuge in the country's squalid camps.
Abbas will discuss the situation of Palestinian refugees forced out Syria with Lebanese officials, some of whom he will meet in the Palestinian embassy, Sheshniyeh said.
Having already visited Lebanon in 2010 and 2011, Abbas will also discuss the poor living conditions of Palestinian refugees in the small Mediterranean country.
Palestinians in Lebanon are barred from some 70 professions, and prohibited from owning property.
Last year, an NGO described living conditions of Palestinians in Lebanon's camps as the "worst of the region".
The American Near East Refugee Aid group cited discrimination, isolation, poverty, joblessness, poor housing and a lack of proper schools, clinics, hospitals and sewage systems as problems affecting Palestinian refugees in Lebanon.