The United States cites “operational security” to justify keeping Pakistani officials in the dark over a drone strike that, Washington claims, led to death of Afghan Taliban chief Mullah Akhtar Mansour.

"Operational security trumps the need to inform other governments," deputy spokesman for the US State Department Mark Toner told reporters during a news briefing in Washington, DC, on Tuesday.

He was responding to remarks by Pakistani Interior Minister Chaudhry Nisar Ali Khan, who denounced the airstrike carried without Islamabad’s knowledge.

On Saturday, the US Department of Defense announced that it had mounted the strike against Mansour “in a remote area of the Afghanistan-Pakistan border region,” sparking fury from Islamabad.

US officials, including Secretary of State John Kerry, have strongly defended the strike, while Pakistanis believe the move is tantamount to violation of their sovereignty.

The Pentagon said that the US forces targeted the Taliban leader because he was engaged in a plot that posed "specific, imminent threats" to US and US-led coalition troops in Afghanistan.

In his Tuesday statement, Toner also took the chance to censure Islamabad for not doing enough to end terrorism.

"You know we have been very clear-eyed and very clear in our interaction with Pakistan where we've believed that they need to do more to root out terrorists, as I said who find safe haven in some of their territory. And we're going to continue to do that," he said.

The US forces regularly use drones for airstrikes and spying missions in Afghanistan as well as Pakistan’s northwestern tribal belt near the Afghan border, allegedly to fight terrorism.

Pakistani authorities have not yet confirmed Mansour’s death while there were conflicting reports quoting various Taliban members, confirming or denying his demise.

The Afghan intelligence agency, National Security Directorate (NDS), is the most credible source that has confirmed the terrorist’s death.

Kabul, meanwhile, accuses its southern neighbor of sheltering and supporting terrorists on its soil, an accusation Islamabad categorically denies.

Terrorism is still on the rise in the region despite about a decade and a half of a US-led war in the country.