U.S. drops 'mother of all bombs' in Afghanistan, aiming for ISIS caves

The United States dropped a massive GBU-43 bomb, nicknamedthe "mother of all bombs," in eastern Afghanistan on Thursday against a series of caves used by ISIS militants, the military said.

The 9.8-tonneGBU-43 bomb was dropped from anMC-130 aircraft in the Achin district of Nangarhar province,close to the border with Pakistan, Pentagon spokespersonAdam Stumpsaid.

It was the first time the United States has used this sizeof conventional bomb in a conflict.

U.S. President Donald Trump described the bombing as a "very successful mission." It wasn't immediately clear how much damage the device did.

The bomb was first testedin March 2003, just days before the start of the Iraq war.When it was developed in the early 2000s, the Pentagon did a formal review of legal justification for its combat use.

During last year's presidential election campaign, Trumpvowed to give priority to destroying ISIS. Lastweek, he ordereda cruise missile attack on aSyrian government airbase in retaliation for a poison gasattack.

"If you look at what's happened over the last eight weeks and compare that really to what's happened over the last eightyears, you'll see that there's a tremendous difference," Trumptold reporters at the White Houseon Thursday.

'Large, powerful, accurately delivered'

He said the bombing "targeteda system of tunnels and caves that ISIS fighters used to movearound freely, making it easier for them to target U.S. militaryadvisers and Afghan forces in the area."

Spicer said the bomb was dropped around7 p.m.local timeand described it as "a large, powerful and accurately deliveredweapon." U.S. forces took "all precautions necessary to preventcivilian casualties and collateral damage," he said.

'Maximizing destruction'

Army Gen. John W. Nicholson, commander of U.S. forces in Afghanistan, said in a news release the strike was designed to minimize the risk to Afghan and U.S. forces conducting clearing operations in the Achin area "while maximizing the destruction" of ISIS fighters and facilities.

He said ISIS has been using improvised explosive devices, bunkers and tunnels to strengthen its defences.

"This is the right munition to reduce these obstacles and maintain the momentum of our offensive against ISIS-K," he added, using the U.S. military's acronym for the ISIS affiliate.

U.S. officials say intelligence suggests ISIS is based overwhelmingly in Nangarhar and neighbouring Kunar province.

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Estimates of its strength in Afghanistan vary. U.S. officials have said they believe the movement has only 700 fighters, but Afghan officials estimate it has about 1,500.

ISIS's offshoot in Afghanistan is suspected of carrying out several attacks on minority ShiaMuslim targets.

The Afghan Taliban, who are trying to overthrow the U.S.-backed government in Kabul, are fiercely opposed to ISIS and the two groups have clashed as they seek to expand territory and influence.