ROSALIO HUIZAR HANDOUT - MUST COURTESY ROSALIO HUIZAR)

ROUGH CUT (NO REPORTER NARRATION).

STORY: At least 20 police horses escaped from their trailers and bolted through the streets of Mexico City on Monday as the sprawling capital was on a high security alert for President Enrique Pena Nieto's state of the union address, local media reported.

According to Mexico City daily El Universal, the horses fled from their trailers in a suburb in the eastern center of the Mexican capital. They were to be deployed alongside riot police to control protesters near Mexico's congress but soon took flight down Mexico City's busy streets, bolting through vehicles in the car-clogged metropolis.

Authorities were deployed to round up the animals, with eight of the horses reportedly found with injuries to their hoofs. No deaths were reported.

The incident has sparked criticism of horse-mounted police operations in sprawling Mexico City.