The smugglers, who had passed into Lebanon from Syria, fled after a 10-minute gunbattle, and none was arrested, officials said. Lebanese soldiers then used bulldozers to close off illegal smuggling routes.
The clashes came as the United Nations pressured Syria to demarcate its border with Lebanon, after the withdrawal of Syrian troops from its smaller neighbor in April last year. The Lebanese government has urged the same, saying such clashes would not happen if the border were drawn and secured.
Syria has said it does not object to border demarcation, but at a later stage because of current tension between Damascus and Beirut's government, dominated by anti-Syrian politicians, according to the AP.
Lebanese-Syrian relations have deteriorated since last year's assassination of former Prime Minister Rafik Hariri. Anti-Syrian politicians in Lebanon have accused Syria in Hariri's killing, a charge Damascus has repeatedly denied.
Friday's incident occurred at around 11 a.m. (0800 GMT) when an army patrol that was working to block illegal smuggling routes came under fire in the Lebanese village of al-Thawiri, about five kilometers (3.1 miles) from the Syrian border, Lebanese officials said on condition of anonymity because they were not authorized to talk to the media.