A US Air Force C-130J Hercules aircraft in Alaska on July 20. US Air Force Photo

The US has deployed the largest nonnuclear bomb in its inventory on an ISIS target in a remote part of far northeast Afghanistan, according to the Pentagon.

US forces in Afghanistan dropped the GBU-43/B Massive Ordnance Air Blast Bomb, whose acronym has inspired the nickname "Mother of All Bombs," over the Achin district of Afghanistan's Nangarhar province, which borders northwest Pakistan.

The MOAB, which was developed during the Iraq War, is the US's largest nonnuclear bomb and had not been used in combat until now.

The 30-foot-long bomb weighs 21,000 pounds — 18,700 pounds of which is the warhead — and was dropped from a C-130 aircraft a little after 7 p.m. local time on Thursday, the Pentagon said.

"This is a weapon that would be used against a large footprint on the ground," CNN analyst Barbara Starr said. The target in question was reportedly an ISIS complex of tunnels, caves, and a camp where personnel were assembling.

The bomb explodes in the air above its target and creates overpressure designed to crush tunnels and everything in them.

The area is very close to the Pakistan border, Starr said, and "is still a border that is not really controlled."

"And they have seen ISIS develop on the Afghanistan side of the this border," she added.

A Massive Ordnance Air Blast weapon, aka the "Mother of All Bombs," being prepared for testing at the Eglin Air Force Armament Center in 2003. DoD Photo

"At 7:32 p.m. local time today, US forces - Afghanistan conducted a strike on an ISIS-K tunnel complex in Achin district, Nangarhar province, Afghanistan, as part of ongoing efforts to defeat ISIS-K in Afghanistan in 2017," US Central Command said in a statement, referring to the ISIS branch in Afghanistan and Pakistan, ISIS-Khorasan.

"The strike used a GBU-43 bomb dropped from a US aircraft," the statement said. "The strike was designed to minimize the risk to Afghan and US forces conducting clearing operations in the area while maximizing the destruction of ISIS-K fighters and facilities."

"As ISIS-K's losses have mounted, they are using IEDs, bunkers, and tunnels to thicken their defense," Gen. John W. Nicholson, the commander of US forces in Afghanistan, said in the statement. "This is the right munition to reduce these obstacles and maintain the momentum of our offensive against ISIS-K."

Russia, Pakistan, and China have also warned of increasing ISIS activity in Afghanistan.

Afghanistan's Nangarhar province borders Pakistan is the border area is hard to control. Google Maps/Christopher Woody

The Central Command statement said US forces "took every precaution to avoid civilian casualties." However, the size and power of the MOAB means damage to the surrounding area can be extensive.

"Dropping a 21,000 lb bomb is not exactly a battle," journalist Jeremy Scahill said on Twitter about the bombing. "It's a mass killing machine."

The MOAB's deployment comes just a few days after a US Special Forces operator was killed in the same region of the country during operations against ISIS.

"The soldier was mortally wounded late Saturday during an operation in Nangarhar Province," US Navy Capt. Bill Salvin said on Twitter on Saturday.

You can see video footage of the MOAB below:

The Taliban has also been resurgent in Afghanistan in recent months, reclaiming territory that US-coalition forces had long fought to hold. In 2016, Afghanistan reportedly lost almost 15% of its territory to Taliban control.

Other important development programs, including education, infrastructure, and women's rights, are reportedly foundering.

Members of the Taliban gather at the site of the execution of three men accused of murdering a couple during a robbery in Ghazni Province. Thomson Reuters

In recent months, civilians have come under fire, both from ISIS and Taliban attacks and from coalition forces. Questions have been raised about how US officials apportion compensation in incidents where Afghan civilians are killed in US-led military operations.

US conduct in Afghanistan has also attracted criticism. The International Criminal Court has said US forces may have committed war crimes in Afghanistan through the "cruel or violent" interrogation of detainees, mostly from 2003 to 2004.

Numerous US military officials have also expressed concern about Russian activity in the country. Afghan officials have said Iran and Pakistan have provided aid to the Taliban.

Opium-poppy cultivation in Afghanistan has steadily increased over the last 15 years. UNODC

Army Gen. Joseph Votel, the chief of US Central Command, has said the war in Afghanistan has settled into a stalemate and that he thought "it will involve additional forces to ensure that we can make the advise-and-assist mission more effective."

The US-led war in Afghanistan will enter its 16th year in 2017. This spring, 300 Marines are scheduled to deploy to the country.

Even after 15 years of occupation, opium cultivation in the country has risen, going up 10% in 2016, according to the UN Office on Drugs and Crime.

Afghanistan's deputy minister of the interior for counternarcotics said the country's campaign against drugs was failing.

"The government is too busy fighting against terrorism and the Taliban and is losing the battle against drugs," he said in October, "but everything is interconnected."

The US has deployed heavy ordnance in the country before.

In November 2001, during the initial invasion of Afghanistan, the US dropped "daisy cutter" bombs — which weighed 15,000 pounds and were first used to clear helicopter landing zones in the jungles of Vietnam — on Taliban positions.