Eight hundred Central American migrants were rounded up and hauled onto buses by Mexican national guardsmen and immigration agents after crossing into the country early Thursday and walking for hours along a rural highway.

The migrants had stopped for the day at a shaded crossroads when hundreds of national guard troops advanced their lines to within 100 yards of the migrants.

A brief negotiation stalled after Mexican authorities said the migrants "demanded permits for free transit through Mexico to the United States."

The migrants knelt to the ground in prayer and began to chant "we want to pass."

National guardsmen in riot gear advanced banging their plastic shields with batons and engaged the migrants. There was shoving and pepper spray as migrants were rounded up.

Many of the people allowed themselves to be escorted to 20 waiting buses without resistance. Women cradling small children or holding kids' hands wept as they walked toward the buses.

Others resisted and were subdued by guardsmen. One man dragged by four guardsmen shouted "they killed my brother, I don't want to die," presumably in reference to the possibility of being returned to his country.