The Trump administration is moving ahead with plans to make it easier for the CIA and the military to target terrorists with drone strikes, even if it means tolerating more civilian casualties, U.S. officials told NBC News.

The military already has declared that parts of Yemen and Somalia are war zones — "areas of active hostilities" in Pentagon parlance — which means the U.S. has greater latitude to launch strikes even if civilian deaths are possible.

That is part of a broad policy shift underway, U.S. officials say, to grant the CIA and the military more autonomy to target and kill al Qaeda and ISIS militants without presidential sign-off in countries such as Yemen, Somalia, Iraq, Syria, Libya and Afghanistan.

"Some of the Obama administration rules were getting in the way of good strikes," said one U.S. official briefed on the matter.

The Obama administration put in place a rule that no drone strike could take place outside a war zone unless there was a "near certainty" that no civilian would be harmed. Obama also put the White House in the decision loop on most strikes against high-value targets. And, outside a war zone, the military or the CIA had to show that the target posed an imminent threat to the United States.

These and other rules — along with a general policy preference by Obama — led to a dramatic drop in drone strikes toward the end of the Obama presidency. The drop was also due to the fact that the al Qaeda threat in Pakistan diminished considerably.

"Some of the Obama administration rules were getting in the way of good strikes."

At the height of the Obama drone campaign against al Qaeda in Pakistan, the U.S. was carrying out an average of two strikes a week, according to various organizations that track the strikes through media reports. Many of those were so-called "signature strikes" against masses of militants whose names were not necessarily known.

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By contrast, there were just 38 drone strikes in Yemen last year and three in Pakistan, according to Long War Journal, a web site that counts them. And the administration moved away from signature strikes, which tended to have a higher chance of mishap.

To be clear, none of this applied to the fight against ISIS in Iraq and Syria, which was and is being waged as a military campaign under the laws of war.

An unmanned U.S. Predator drone flies over Kandahar Air Field, southern Afghanistan, on Jan. 31, 2010. Kirsty Wigglesworth / AP, file

But the Obama drone rules constrained the U.S. military last year in Yemen, according to a senior U.S. official briefed on the matter. After Al Qaeda in the Arabian Peninsula made gains, the United Arab Emirates sent troops in April to retake territory seized by the group. But the U.S. was unable to fully support the operation with drone strikes because it couldn’t show that each target posed an imminent threat to Americans, the official said.

A flurry of strikes in Yemen in recent weeks, against targets that had long been previously identified, was made possible by declaring parts of Yemen a war zone, the official said. The Pentagon no longer had to show that the targets posed an imminent threat to the U.S. or declare a near certainty that no civilian would be harmed.

A military commander can decide whether the risk of civilian casualties is "proportional" to the benefit of the strike, under the international law of war.

A senior defense official said that whether the rules allow it or not, the military makes every effort to avoid civilian casualties in its targeted strikes.

The official said that bomb damage assessments have found no civilian casualties in the recent Yemen strikes, which were against fighting positions and equipment.

U.S. Central Command says that at this time it does not have any credible reports of operations in Yemen resulting in civilian casualties, beyond the four to 12 estimated deaths from the January 29 SEAL raid.

Trump also appears to be reversing a policy preference by Obama to get the CIA, for the most part, out of the drone-killing business. A drone strike in Syria last month that killed Abu Hani al-Masri, a longtime terrorist with ties to Osama bin Laden, was the work of the CIA, U.S. officials told NBC News. Previously, the CIA had not been carrying out drone strikes in Syria.

Human rights groups, which fought for years to get Obama to rein in drone strikes, are dismayed by the Trump approach. At the same time, some former Obama officials told NBC News that many counter terrorism decisions were "over-lawyered" in Obama’s National Security Council.

Many military and CIA officials welcome the changes, say officials. So far, no Democrat in Congress has voiced a public objection.

However, a group of former Obama administration officials and others sent Defense Secretary James Mattis a letter over the weekend urging that protection of civilians remain a top priority as the government reconsiders counter terrorism policies.

"I am concerned that loosening standards will harm our ability over time to carry out these operations, because it will affect our standing with the countries in which we need to operate," said Matt Olsen, a signer of the letter and the former head of the National Counterterrorism Center.

"I think these rules proved effective operationally — I never saw an instance where we missed an opportunity to carry out a strike because of too much lawyering."