WASHINGTON — Once described as an ill-equipped band of insurgents, the Taliban are increasingly attacking security forces across Afghanistan using night-vision goggles and lasers that United States military officials said were either stolen from Afghan and international troops or bought on the black market.

The devices allow the Taliban to maneuver on forces under the cover of darkness as they track the whirling blades of coalition helicopters, the infrared lasers on American rifles, or even the bedtime movements of local police officers.

With this new battlefield visibility, the Taliban more than doubled nighttime attacks from 2014 to 2017, according to one US military official who described internal Pentagon data on the condition of anonymity. The number of Afghans who were wounded or killed during nighttime attacks during that period nearly tripled.

That has forced American commanders to rethink the limited access they give Afghan security forces to the night-vision devices. Commanders now worry that denying the expensive equipment to those forces puts them at a technological disadvantage, with potentially lethal consequences.

For years, American commanders have been reluctant to give night-vision equipment to rank-and-file Afghan soldiers and police officers out of concern of widespread corruption among those forces.

The devices — headsets and infrared lasers — are usually given only to elite Afghan commandos and police special mission units, according to US military officials.

As some of this equipment falls into Taliban hands, the militants are joining a larger trend, said David W. Barno, a retired lieutenant general who led the war effort in Afghanistan from 2003 to 2005.

Advanced equipment, such as drones and precision weapons, is being seized by other extremist groups in other global conflict zones, he said.

“It’s going to be a problem,’’ Barno said, “and it’s going to change how we operate.’’

With the spread of the devices, infantry units on patrols have been told not to use certain marking devices that can be seen only by night-vision equipment. Helicopter crews have been made distinctly aware that their aircraft are no longer cloaked by darkness.

In one case last November, Taliban fighters wearing night-vision goggles attacked a police outpost in Farah province, in western Afghanistan. By the time the predawn assault was over, eight Afghan officers lay dead in their beds, Haji Abdul Rahman Aka, the elder of the province’s Pule Regi area, said at the time. Only one Afghan officer survived.

The frequency and ferocity of the nighttime Taliban attacks are linked to attempts by Afghan forces, based in small checkpoints across the country, to hold territory that has been wrested away from the militants.

Previously unreported documents, obtained by The New York Times, underline concerns about the Taliban’s growing sophistication on the battlefield after 16 years of war — and American commanders’ efforts to stunt it.

The documents show that the US military has begun to send older models of night- vision hardware to regular Afghan army units. Those headsets cost an estimated $3,000 each, officials said.

One of the first batches of night-vision equipment for conventional units in southern Afghanistan, part of a monthslong pilot program, was sent to the embattled 215th Corps in Helmand province in the spring of 2016.

Only 161 of the 210 devices were returned, according to the military documents obtained by The Times, and the equipment was not effectively used, in part because the forces were not properly trained to use it.

Afghan troops said the missing devices were reported as “battle losses,’’ but could not support that claim with any proof or records to explain where or when they were left behind, according to the documents.

At the time, the commander of the 215th Corps was Major General M. Moein Faqir. He was later arrested on sweeping corruption charges that included misuse of food money meant for his troops.

Last year, and with better results, night-vision equipment was sent to the 205th Corps, located around Kandahar, the military documents showed. Five devices were lost between July and December, when the program ended, according to the documents.

Over the summer and fall, the Afghan National Army suffered 15 percent fewer casualties around Kandahar than it had during the same period in 2016. The documents credited the night-vision equipment for the marked reduction.

The US military is now planning to equip the unit with roughly 2,500 night-vision goggles.

But despite the measured successes, it remains unclear if the US military will give the devices to the rest of the Afghan army.