Acting on a tipoff, security forces on Wednesday stopped the truck in the southern province of Hatay on the Syrian border, Hurriyet newspaper reported.
A significant quantity of ammunition and weapons were discovered in the truck, whose drivers claimed they were carrying aid on behalf of the pro-Islamic Humanitarian Relief Foundation (IHH).
But IHH dismissed the allegations as "slanderous".
"Our organisation has nothing to do with this case," a spokesman for the relief group told AFP.
Turkey is a vocal critic of Syrian President Bashar al-Assad and has openly supported the rebels fighting his regime, but has always denied arming them.
In December, local media reported that Turkey had shipped 47 tonnes of weapons to the rebels since June.
But Defence Minister Ismet Yilmaz denied weapons of war had been sent to Syria, saying only hunting rifles had been exported.
Turkey, which has been accused of turning a blind eye to fighters crossing its border into Syria, is sheltering about 600,000 Syrian refugees who have fled the civil war as well as the main Syrian opposition group.
COMMENTS (1)
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ
47 tonnes of hunting rifles? Maybe this muslim brother meant rifles that hunt humans, and are automatic, with armor piercing ammo.