Fighting in Tripoli is indicative of rising Sunni-Shiite tensions as the formation of a new government hits an impasse. Religious leaders called for calm Wednesday.
The agreement gives Hezbollah and the opposition allies of the Shiite militants enough control in the government to have veto power over legislation.
The Lebanese Army, which many credit with holding together the fragile nation, is under siege after firing on a protest last month.
The Arab League's secretary-general flies into Beirut this week in an effort to end the country's presidential stalemate.