Since President Nicolas Maduro deepened his crisis-wracked country's isolation last week by ordering the closure of the Brazilian border, small groups of Venezuelans have nevertheless been emerging on the Brazilian side.

Denied the option of using the main crossings, they have been forced to negotiate treacherous mountain trails and run the gauntlet of unpredictable Venezuelan border police.

Later, they return along the rocky trails, weighed down with bags loaded with medicine and food for relatives who often lack the basics.

But Cesar Marcano won't be going back.

A policeman in Venezuela, he became one of more than 300 deserters from the armed forces this week.

With his young son on his back, Marcano, his wife and children are part of the groups on the trails who are only making a one-way trip.

The situation has become "too difficult. They are doing really bad things," he said.

"I had to come here and leave the police. I am a deserter, I cannot enter Venezuela again. If I enter again, I'll be locked up," he said.

It takes 30 minutes to walk to the other side over the trails, skirting around Venezuelan border posts -- but it takes an hour if Venezuelan National Guard patrols are spotted.

Many people pay porters who know the way and can help them carry their load.

Marcano and his family have arrived from Santa Elena de Uairen, a town on the Venezuelan side of the border, 20 kilometers (12 miles) from the Brazilian town of Pacaraima.

"We spent five days in Santa Elena going hungry and sleeping in the square, before we were able to get here. We managed to talk to the guards and they left us alone -- they even gave us some help to get through the trails," he said.

It's not always so easy.

"Trying to pass the guards is very problematic," said Rober, one of the smugglers-turned-porters who have been making a living helping people negotiate the mountain trails since the beginning of Venezuela's crisis in 2015 -- when many came to settle in Brazil's Roraima state.

But the border closure hasn't made their lives any easier.

"They do not want us to bring across food. They are shutting down the border. Everything's a problem. We cannot work, we cannot eat with the border closed," he said.

From the crest of a hill, a group of Venezuelans carefully observe the other side of the border, under a punishing sun.

Edile, a woman aged around 60, was preparing to cross back into Venezuela.

"We have a relative who is sick and needs surgery, and there are medications there to help him so he can face his operation," she said

Rober, the smuggler, carries her bags past a Brazilian guard post.

"You can go, the path is clear," one of the guards says.

For Rober and the other porters, the mountain has become their livelihood.

"It's dangerous because we can slip and fall on the mountain. You have to climb up, climb down, always with an eye out for the guards," he said.

There are no guarantees on the mountain trails.

"They can hit us, mistreat us, they can kill us," said Rober.

A woman concurs, saying her husband, a smuggler, has just been arrested along the same trail.