Hundreds of Libyans turned over their weapons at collection points in the capital and the eastern city of Benghazi on Saturday following rallies which called for disarmament and the disbanding of militias.
A steady trickle of men surrendered their weapons to national army troops stationed in Tripoli's Martyrs Square and in Benghazi's Freedom Square, AFP journalists reported.
"We are astonished by the positive turnout," said Colonel Hussein Abdullah Khalifa in Tripoli, adding that the initiative was galvanised by anti-militia rallies pressing for a united army held in Libya's two largest cities this month.
Tripoli campaign organiser Ziad Hadia told AFP that "more than 100 people had turned in light, medium and heavy weapons as well as ammunition ranging from bullets to tank shells" in the first half of the day.
"We also received three heat-seeking missiles," he added, while one person had come forward with a tank which is to be delivered to the army later at an undisclosed location.
In Benghazi, the army tallied more than 200 weapons, an AFP journalist said.
Those numbers represent just a tiny fraction of the arms that spilled out of the arsenals of toppled dictator Moamer Kadhafi but it was seen as a step forward in a country where many cling to their weapons citing insecurity.
"To achieve security we must take the first step ourselves," said Mustafa Abu Hmeid, a 23-year-old mechanic clutching a rifle, a treasured spoil of the 2011 conflict which ended in Kadhafi's ouster and death.
Housewife Mariam Abu Swera expressed relief: "As long as there are arms on the streets, I can't move freely or go about my normal life, so we really welcome this step."
The collection drive is a collaboration between the national army and private television station Al-Hurra, which drummed up support through its live broadcasts from Tripoli and Benghazi.
Organisers in both cities will raffle off prizes, including two cars, at the end of the day-long collection. They said the process was not a one-off event and would be repeated to include other cities.
A September 11 attack that killed four Americans in Benghazi, including the US ambassador, was followed by mass anti-militia protests in the city, increasing pressure on Libyan authorities to tackle insecurity.
On Friday, hundreds of people rallied in Tripoli in support of a national army and against armed groups.