UNITED NATIONS -- UN Secretary-General Ban Ki-moon is alarmed by the spillover of the Syrian unrest to Lebanon, a UN spokesperson said on Monday.

During the daily news briefing here in UN's headquarters, Ban' s spokesman Martin Nesirky told reporters that the UN Special Coordinator in Lebanon, Derek Plumbly, has expressed his concerns about the recent fighting in Lebanon.

"The Secretary-General is alarmed by the spillover of violence from Syria into Lebanon" Nesirky said.

The conflict in Syria has increasingly spilled over into Lebanon, with Hezbollah militant group dispatching fighters to battle alongside the Syrian army against rebel forces.

At least one member of Hezbollah and 10 Syrian rebels were killed in clashes erupted Sunday on the outskirts of Baalbek in east Lebanon. The clashes came after a barrage of rockets fired from Syrian territory at Hezbollah strongholds in Lebanon in recent days.

The U.S., Russian and UN officials will hold a three-way meeting to further the preparations for the international conference on Syria envisioned under the U.S.-Russian initiative. Lakhdar Brahimi, the Joint Special Representative for Syria, and Jeffrey Feltman, the Under-Secretary-General for Political Affairs, will be present at that conference, according to Nesirky.

The U.S. and Russia agreed in early May to sponsor another international conference in Geneva to end the 26-month-old conflict, which has killed more than 70,000 people, left 6.8 million people in need and driven 1.5 million Syrians as refugees abroad.