The truck was stopped as it drove into Beirut from the Bekaa Valley to the east, Information Minister Ghazi Aridi said.
A cabinet source said the truck had been loaded with hand guns and assault rifles hidden under a blanket of animal feed.
Hizbullah demanded the return of the truck and said the supplies were heading to its fighters in south Lebanon.
Hizbullah said the authorities had confiscated a “truck carrying munitions to the resistance”. The truck had been carrying the load from the Bekaa Valley in the east to the south, it said in a statement.
“The government program clearly confirms the right of the resistance ... to work to liberate the rest of the occupied land, the prisoners and to confront the Zionist threats,” the statement said, demanding the return of the truck and munitions.
Civil unrestThe government is facing a political challenge from opponents including Hizbullah. The political standoff spilled over into armed clashes between supporters of the rival camps last month and nine people were killed.
It was Lebanon’s worst civil unrest since its 1975-1990 civil war and raised fears of a new conflict. Leaders on both sides called for calm.
A United Nations envoy and anti-Syrian Lebanese leaders have accused Syria of smuggling weapons to its allies in Lebanon in recent months.
The rival camps have accused each other of using militias in the recent violence, stirring memories of the civil war which started as a conflict between Christians, Muslims and Palestinians and drew in states including Israel and Syria.
Hizbullah, the most powerful military force in Lebanon, has vowed not to use its weapons against other Lebanese. Hizbullah, backed by Syria and Iran, and its allies in opposition are demanding veto power in cabinet and early elections.
The government, whose backers include the United States, France and Saudi Arabia, has refused to yield.
Attacks on peacekeepers possible
Lebanese Defense Minister Elias Murr said Thursday that there were intelligence reports of possible attacks being planned against international peacekeepers in Lebanon.
Murr said there were reports that “fundamentalist groups” in the Palestinian refugee camp of Ein el-Hilweh in southern Lebanon, were contemplating attacks against the peacekeepers.
“Whether this information is true or not, we have to deal with it very carefully … even it is has zero credibility,” he said.