It's a tense situation for thousands of people living in Rio Bravo and Matamoros following reports of grenade explosions and armed clashes between the military and drug traffickers.
It all happened late Wednesday afternoon.
Matamoros residents used the #matamoros hashtag of Twitter to report gunfire and clashes between the military and armed men.
Several blockades were reported and photographed throughout Matamoros.
Rio Bravo residents reported a series of strong explosions downtown.
They reported that grenades had detonated.
It's not clear if there was anybody injured or killed during the incidents.
Mexican authorities have not released any official information about what happened.
Action 4 News will provide more information as it becomes available.