TECATE, Calif. — With flames encircling the remote border crossing east of San Diego, U.S. Customs inspectors wasted no time evacuating. They closed the gate blocking the lanes into California, wrapped a chain around it, and snapped on the lock.

The Tecate Port of Entry officially was closed.

But not for long.

Minutes later on Sunday afternoon, someone cut the chain. The gate swung open. People began rushing through the unguarded crossing.

"Who knows if they had papers or not?" said Adan Nunez Estrada, a Mexican Customs inspector who works at the crossing.

The Harris wildfire burning the U.S.-Mexico border has created both opportunities and deadly traps for migrants, four of whom were found dead Thursday. The fires also have made the difficult job of patrolling even tougher.

Already stretched thin across the rugged mountains east of San Diego, more than 200 federal border officers have been redeployed to fire-related emergencies. Many of the remote roads they usually patrol remain soot-coated and inaccessible.

U.S. and Mexican officials say they have the scorched frontier under control — and that the fires appear to be stopping immigrants when law enforcement cannot.

"There's not much border patrol around," said Luis Enrique Delgado, a Mexican immigrant safety officer from Tecate, "but many immigrants see the smoke and turn back."

Still, catastrophe breeds chaos and some people can't resist seizing the moment, especially when other options -- such as crossing hot deserts or swift rivers -- might seem even more perilous.

"This is their big chance. Everybody's doing other things," said Joseph Cisneros, who lives near rural Barrett Lake and regularly sees migrants on his property.

Since the blazes started, agents have arrested more than 200 migrants in the fire area, many after being smoked out of ravines and trails. Some may have started to cross before the fire. But some likely decided to cross because of the opportunity it provided.

Four badly burned men climbed out of a flame-filled canyon Sunday night. California Department of Transportation worker Don Elms, driving by on State Highway 94, got them inside his truck, where they doused themselves in water and pressed their blistered hands against the air-conditioning vents.

"They were hurting bad. They were moaning and groaning," said Elms.

All four remained in critical condition Thursday at the University of California-San Diego Medical Center's burn center, along with 10 other suspected illegal border crossers rescued from the fire.

In Tecate on Sunday, inspectors at the small port of entry saw few options as the flames roared down the surrounding hills. One man died trying to save his home, and four firefighters were injured. With the roads north shrouded in smoke, the inspectors fled into Mexico, locking the gate behind them.

After someone opened the gate, the rush was on, said Nunez. People started walking and driving back and forth unimpeded. Most, he said, appeared to be U.S. residents who had been visiting Mexico and were rushing back across the border to get their parked cars away from the flames.

Some people, however, disappeared into the hills west of town. Suspected looters may have been among them. On Wednesday, two people were arrested heading south toward Tecate, carrying a bagful of items they allegedly took from a burned-out residence on the U.S. side.

The crossing stayed unguarded for about 30 minutes, until border patrol agents and sheriff's deputies made their way back through the flames and restored order, Nunez said. Since the incident, several agents have been monitoring the border crossing, which has remained closed except to Mexican firefighters coming to lend a hand in California.

"I don't blame the customs guys for getting out," said one U.S. law enforcement source who spoke on condition of anonymity because he is not authorized to speak with the media. "They could have been killed."

Because of the incident, customs officials will look into getting a taller gate and more substantial chains, said Vincent Bond, a spokesman for Customs and Border Protection.

Los Angeles Times staff writer Ari B. Bloomekatz contributed to this report.