Residents in Arsal told al-Jazeera what was believed to be a Syrian fighter jet flew about 12 miles into Lebanese territory before firing on the town. There were no casualties reported, though witnesses said some homes were damaged.
Lebanese security sources told The Daily Star newspaper on condition of anonymity that unknown gunmen fired on Syrian tanker trucks trying to cross the border Wednesday from Tripoli.
Lebanon's national security has come under threat from the civil war in Syria. March marked the seventh anniversary of the Cedar Revolution in Lebanon, which broke Syria's grip on Lebanese affairs.
The U.S. State Department this week urged U.S. citizens to avoid traveling to Lebanon because of the security situation. The warning said that civil war in Syria has "resulted in numerous security incidents in the border regions between Lebanon and Syria and coincides with an increasing number of security incidents around the country."
Lebanon's prime minister, a Hezbollah ally, resigned amid internal squabbling over top security positions in the country. Hezbollah Deputy Secretary-General Naim Qassem said in comments published by The Daily Star that Lebanon's "stability is in everybody's interest."