At least five people were reported to have been killed and another 20 were injured in clashes in Tripoli in northern Lebanon. The violence was believed to be tied to the conflict in neighboring Syria.
U.S. Ambassador to Lebanon Maura Connelly met in Beirut with Lebanese Prime Minister Najib Mikati to express her concern about regional events.
"The ambassador expressed the United States' concern with the security situation in Tripoli and commended the government's efforts to defuse the situation," a statement released by the embassy read.
Weekend clashes in Tripoli erupted after Lebanese authorities arrested Sunni cleric Shadi al-Mawlawi on charges of supporting terrorist groups.
Syrian influence weighed heavy on political affairs in Beirut before the Cedar Revolution in Lebanon prompted Syrian forces to leave the country in 2005.
Connelly said Washington was committed to ensuring Lebanon remained a stable, sovereign and independent country.
Violence in neighboring Syria has raged for more than a year. The country agreed to the terms of a peace deal brokered by former U.N. Secretary-General Kofi Annan, though there are few signs that fighting has ended.