BBC reports that Brazil is sending troops and extra police to the border town of Pacaraima where Venezuelan migrant camps were attacked and set ablaze.
President Michel Temer held an emergency meeting on Sunday as regional tensions rose over the numbers fleeing crisis-hit Venezuela.
Venezuela has asked its neighbour to ensure the safety of its citizens.
In Ecuador, desperate Venezuelans were reported to be crossing the border in defiance of new entry requirements. Hundreds were stranded on Saturday when Ecuador brought in new rules requiring Venezuelans crossing from Colombia to have valid passports rather than just identity cards.