Turkish security forces on Sunday searched seven trucks near the Syrian border suspected to be loaded with weapons and briefly detained three drivers, local media reported.
The operation came just days after Turkish police carried out multi-city raids against Al-Qaeda suspects accused of helping radical fighters in Syria.
The Turkish government itself has been accused by Western powers of shipping arms to rebels and turning a blind eye to militants crossing the border to fight in Syria, claims it has repeatedly denied.
CNN-Turk television said a large team of security officials stopped the trucks on a road in southeastern Turkey and held three drivers before releasing them and their vehicles.
It said the trucks belonged to Turkey's National Intelligence Organisation (MIT) and were carrying humanitarian aid.
Three weeks ago, security forces stopped a truck on the Syrian border suspected to have been carrying weapons and ammunition on behalf of the Humanitarian Relief Foundation (IHH), a charity linked to the government.
The IHH dismissed the claims as an attempt to discredit the organisation, while media reports said the convoy had been accompanied by MIT agents.
Police last Tuesday detained 25 suspects including two reported top Al-Qaeda operatives and an IHH staff member suspected of a variety of offences including sending fighters to Syria and raising money for Syrian rebels.
Turkey is a staunch opponent of the Syrian regime of President Bashar al-Assad and hosts the exiled opposition but has denied shipping weapons to the rebels.
However, in December, Turkish media -- quoting UN and government documents -- reported that the country had shipped 47 tonnes of arms to the rebels since June last year.