BEIRUT — Lebanese troops have sealed off a town near the Syrian border after attackers ambushed an army force, killing two soldiers and wounding others, the state-run National News Agency reported Sunday.

The agency said special forces set up checkpoints on roads leading to the town, Arsal. Troops were also deployed in fields around the town to try to prevent gunmen from escaping.

The troops were ambushed Friday while trying to detain a fugitive, Khaled Hamid, suspected of involvement in the 2011 kidnapping of seven Estonian tourists. They were abducted in Lebanon’s eastern Bekaa Valley and held for nearly four months before being released in July that year.

Some security officials have said that Hamid crossed the border into Syria over the past months to fight with rebels trying to depose Syrian President Bashar Assad. Many in Arsal, a Sunni Muslim town, are sympathetic to Syrian rebels.

Many in Lebanon fear Syria’s civil war could spill across the border.

Lebanon and Syria share a complex web of political and sectarian ties and rivalries which are easily enflamed. Lebanon, a country plagued by decades of strife, has been on edge since the uprising against Assad began in March 2011. Deadly clashes between pro- and anti-Assad Lebanese groups have broken out on several occasions.

Many among Lebanon’s Sunni Muslims have backed Syria’s mainly Sunni rebel forces, in which radical Islamists have become increasingly active. Lebanese Shiite Muslims, including the militant Hezbollah, have leaned toward Assad, whose tiny Alawite sect is an offshoot of Shiite Islam.

A Lebanese army general told The Associated Press Sunday that “several people” have been detained on suspicion of involvement in the Friday ambush. The general spoke on condition of anonymity according to regulations.

President Michel Suleiman told the father of Capt. Pierre Bashaalani, who was killed in the ambush, that the army is determined to find all those involved and put them on trial.

Army commander Gen. Jean Kahwaji said in a statement to the troops that “we will not be silent or accept any political deal.” He added that the “army will not retreat no matter what happens and will punish the criminals no matter whom they belong to.”

Lebanon’s LBC-TV showed photographs Sunday of uniformed soldiers being held in the municipality building in Arsal. Some of the soldiers had bruises, and others were bloody.

Some residents in Arsal have said that the troops who were ambushed were in civilian clothes and using civilian cars. They said they believed they were pro-government Syrian militiamen who crossed the border from Syria to capture Hamid.

Prime Minister Najib Mikati said all those involved in the attack on the Lebanese army should be handed over to authorities.

Front Section, Pages 3 on 02/04/2013