U.S. takes fight against ISIS very seriously: White House

Asserting that the United States takes the fight against the Islamic State of Iraq and Syria (ISIS) very seriously, White House press secretary Sean Spicer said that they have denied operational space to the terror group in order to defeat them.

"The United States takes the fight against ISIS very seriously, and in order to defeat the group, we must deny them operational space, which we did." Spicer said in press briefing on Thursday.

Spicer also confirmed that the U.S. dropped the GBU-43/B Massive Ordnance Air Blast Bomb, also known as the "Mother of All Bombs" or "MOAB," over the Achin district of Afghanistan's Nangarhar province to destroy a tunnels and caves network of the Islamic State.

"At 7 p.m. local time in Afghanistan last night the U.S. military used the GBU 43 weapon. It is a large, powerful and accurately delivered weapon. We targeted a system of tunnels and caves that ISIS fighters used to move around freely making it easy for them to target the U.S. military advisors and afghan forces in the area," he said.

Spicer added that they used all necessary precaution to avoid civilian causalities and collateral damage.

Earlier, CNN had reported that the U.S. military has dropped its most powerful non-nuclear bomb in the Achin district of Afghanistan's Nangarhar province to target the Islamic State.

The Nangarhar province borders with Pakistan.

According to the report, a GBU-43/B Massive Ordnance Air Blast Bomb, nicknamed MOAB and also known as the "mother of all bombs" is a 21,600-pound, GPS-guided munition that is America's most powerful non-nuclear bomb.

This is the first time a MOAB has been used in the battlefield, according to the US officials. This ammunition was developed during the Iraq War.

Last week, a Green Beret of the U.S. armed forces was killed during a combat operation against ISIS State in Afghanistan's Nangarhar Province.

American forces in Afghanistan are primarily charged with advising and assisting Afghan security forces as part of NATO's Resolute Support mission, but the U.S. military also conducts counterterrorism combat operations against groups such as ISIS and al-Qaida under its unilateral Freedom's Sentinel operation.