Venezuelans took to dugout canoes to shop in Colombia on Saturday as a government crackdown on smuggling and migrants cut off access to at least six border crossings key to the life of communities on both sides.

The going rate for a short river journey in the wooden canoes was less than a dollar at Venezuela's widely used black market exchange rate. Some of the roughly 50 people waiting to row across Saturday under the eyes of Venezuelan soldiers were locals seeking to fill prescriptions for medicines hard to find in Venezuela.

The crossing between Boca del Grita and Puerto Santander in Colombia is among four additional checkpoints closed Saturday by President Nicolas Maduro in the name of cleaning up smuggling and paramilitary activity on Venezuela's western edge.

The closures have choked off the tide of contraband goods that has been flowing from Venezuela, where products are heavily subsidized, to Colombia, where they can be sold at far higher prices. Venezuelan officials blame that smuggling for causing chronic shortages of key goods.

But the closures have also disrupted lives in a region where many people routinely cross the border to work, shop and visit family. An estimated 5 million Colombians live in Venezuela, many of them dual nationals.

Venezuela's military last week expelled hundreds of Colombians living in a shantytown officials said was a hotbed of smuggling, but has not repeated those raids in recent days.

Still, many locals worry that mass deportations may be on the horizon. Officials estimate that 8,000 Colombians have fled or been deported from Venezuela since the crackdown began.

Martha Restrepo, one of those waiting to cross the river Saturday, said she plans to move back to Colombia after living for 10 years in Venezuela without legal status.

"I'm going because I'm just fed up," she said. "I came here 10 years ago to work, and I'm leaving now because of what Maduro's been saying."

The Red Cross has established emergency housing on Colombia's side of the border, where permanent shelters are already overflowing.

Venezuelan Vice President Jorge Arreaza visited one of the closed border crossings Saturday, and was assailed with complaints that the closure is affecting people's ability to work.

"Colombians and Venezuelan live together here, and we're working to guarantee that everyone can live well from their work," Arreaza said.

Maduro irked many Colombians Friday when he performed one of their country's traditional dances at a rally to support to border closures and expulsion of undocumented Colombians. He was expected to leave for China on Saturday.

"We will not lend our dance to a tyrant," said conservative former Colombian President Alvaro Uribe, who has long waged a war of words with Maduro and his mentor, the late President Hugo Chavez.

On Friday, the United Nations expressed concern about possible human rights violations amid the crackdown, and the U.S. State Department urged Venezuela to pay attention to the "worsening humanitarian situation" along the border, and refrain from deporting refugees.

The Organization of American States plans to hold an emergency session on Monday to discuss the situation, and foreign ministers from South America are to meet on Thursday.

While business has all but ground to a halt in Colombian border towns, Venezuelans grappling with chronic shortages on their side say they've been cut off from supplies they had been finding in Colombia, including food, hardware and other basic supplies.

Lusidia Polanco waited Saturday to cross the border so she could buy sanitary napkins and soap in Colombia. She said she makes the four-hour trip from her hometown each month.

"It's a disaster here. You can't find anything you need," she said.