ISIL terrorists based in Afghanistan had planned to attack American and coalition forces in the war-stricken country, prompting the US to launch drone strikes earlier this week, Pentagon officials say.

According to local Afghan news outlets, a US drone strike killed two senior ISIL leaders and over a dozen militants on Tuesday in the Nangarhar Province in eastern Afghanistan.

Shahidullah Shahid, a former Pakistan Taliban spokesman, and Gul Zaman, the deputy leader of the ISIL in Afghanistan, were killed during the strike, Afghan intelligence officials said.

On Thursday, the Pentagon confirmed that a strike on Tuesday and two strikes on Monday were conducted against "individuals threatening US and coalition forces."

"The strikes were against individuals known to be planning attacks against US and coalition personnel," Pentagon spokesman Navy Capt. Jeff Davis said on Friday.

The spokesman did not provide further details about the kind of attacks planned or where the Takfiri terrorists were going to launch their attacks against US and coalition forces.

"The strikes were precision strikes using unmanned, remotely-piloted aircraft," The Hill cited Davis as saying.

"We do not have any battle damage assessment such that we would be able to confirm specific individuals who [were killed]," he added.

US defense officials believe that ISIL terrorists in Afghanistan are mostly disaffected members of the Taliban who have "re-branded" themselves as ISIL. However, they say it is important to keep the militants under watch.

"We are monitoring closely to see whether this limited re-branding of disaffected Taliban fighters will have a meaningful impact on the ground," said Pentagon spokeswoman Henrietta Levin.

These militants now operate in three provinces including Nangarhar in the east, Farah in the west and Helmand in the south.

Presently, about 9,800 American troops in are stationed at 17 US bases and five coalition bases in Afghanistan.