Venezuelan officials have arrested a hard-line opposition activist on weapons charges.

The arrest Wednesday night comes as a fledgling "anti-coup" unit inside the government targets what it calls renewed attempts by the opposition to destabilize the country.

Human rights groups say the arrest of substitute lawmaker Gilber Caro goes against the government's recent freeing of several jailed activists as part of Vatican-sponsored mediation effort. The opposition is asking the government to free about 100 people widely considered political prisoners as part of the dialogue process.

Caro was arrested at a highway toll station after police said they found a gun and explosives in his car. His Popular Will party says the weapons were planted there to frame him.