Ceasefire agreed in Lebanese border town battle

Lebanese army soldiers an armoured carrier advance towards the Sunni Muslim border town of Arsal, in eastern Bekaa Valley as part of reinforcements August 4, 2014. REUTERS/Mohamed Azakir

BEIRUT (Reuters) - The Lebanese army and Islamist militants agreed a 24-hour ceasefire on Tuesday after four days of fighting triggered by the rebels' seizure of a border town, in the most serious spillover of Syria's three-year civil war into Lebanon.

A security source said the ceasefire would allow time for a mediator to investigate the fate of 22 soldiers missing since the militants seized the town of Arsal on Saturday and to help evacuate civilians, including those wounded in the conflict.