SAN ANTONIO DEL TÁCHIRA, Venezuela — At night and in the early morning, they wade across the thigh-deep river in Colombia, with televisions, refrigerators and other household possessions on their backs. By day, watched by gun-toting soldiers, they line up to cross what was once a busy international bridge now under military lockdown, dragging roller suitcases while their children shoulder school backpacks.

Hundreds of Colombians are fleeing across the border, running from a crackdown on immigrants initiated by Venezuela’s president, Nicolás Maduro.

“It’s heartbreaking,” said Handerles Suárez, 25, a construction worker, as he waited with his wife and baby daughter at dusk to cross the Simón Bólivar Bridge to his native Colombia. He said he had lived in Venezuela for 10 years, but now, seeing his countrymen rounded up and deported, their houses marked for demolition by the government, he decided to leave voluntarily rather than risk the uncertainty of a forced departure.

“Venezuela has given us everything,” he said, tears in his eyes. “It’s been like a second mother to us.”