Tear Gas Thrown at Migrants, Kids as U.S. Closes CA-Mexico Border Crossing

4:34 PM PT -- CBP San Diego says pedestrian bridges between Tijuana and San Diego are now open again in both directions, heading north and south.

Tensions are at a boiling point at the U.S.-Mexico border in California, where migrants have started to clash with border agents ... who've also begun throwing tear gas at them and their children.

U.S. Customs and Border Protection closed the San Ysidro border crossing outside of San Diego Sunday, as hundreds of migrants trying to enter the U.S. -- many of whom are seeking asylum -- gathered at the border and demanded entry. Some of them even started throwing rocks at agents, and U.S. agents reportedly responded by throwing tear gas into the crowd.

The move is drawing heavy criticism, as there are children among the migrants. No shots have been fired, but remember ... President Trump essentially gave the green light for retaliation a few weeks ago as the migrant caravan made its way north.

Needless to say, it's an intense scene. As for a possible solution ... the Trump administration reportedly struck a deal with the incoming Mexican government to keep asylum seekers south of the border as their cases are heard in court.