The U.S. military has opened a new front in the war against terrorists after President Trump granted new authorities for U.S. commanders to carry out air and ground attacks against al Qaeda's most dangerous affiliate in Yemen.

The U.S. has conducted two days of airstrikes aimed at Al Qaeda in the Arabian Peninsula, or AQAP. The new, more aggressive posture comes after Trump gave U.S. Central Commander Gen. Joseph Votel expanded authority to order military action in Yemen, without prior approval from the White House.

Pentagon spokesman Navy Capt. Jeff Davis said the president granted the new authority at the same time he approved the Jan 29 special operations raid that resulted in the death of U.S. Navy SEAL Ryan Owens.

"This was an authority that was delegated by the president, through the secretary of defense to the Central Command commander to carry out," Davis said.

"I don't want to telegraph future operations, but this is part of a plan to go after a very real threat, to ensure they are defeated and denied the opportunity to plot and carry out terrorist attacks from ungoverned spaces," Davis said.

Pentagon sources says military commanders had been frustrated by the slow approval process for strikes under President Obama, which was seen as needlessly cumbersome and often required lengthy decision memos to be submitted to the president.

Under the new procedures, sources say, the Trump will remain informed, but Defense Secretary Jim Mattis and his combatant commanders will be free to take the gloves off as they see fit.

As a result, the U.S was able to carry out more than 30 airstrikes against targets in Yemen over the past two days in a major ramp-up of operations against al Qaeda fighters, attacking targets that the U.S. military has been developing for months.

The strikes were carried out in the pre-dawn hours Thursday and Friday by a combination of manned and unmanned U.S. aircraft, said Davis, who declined to give a specific number. "It depends on how you count strikes. I would say we said more than 20, two nights ago. Last night would put us somewhere over 30."

The strikes are specifically targeting members of AQAP, which Davis labeled the al Qaeda affiliate most intent on attacking the West.

"Make no mistake, AQAP, while we talk a lot about ISIS, AQAP is the organization that has more American blood on its hands. It is a deadly terrorist organization that has proven itself to be very effective in targeting and killing Americans and they have intent and aspirations to continue doing so," Davis said. "We are working to stop them."

He added that while U.S. special operations forces regularly move into and out of Yemen, none was involved in any airstrikes or ground operations this week. Reuters had reported on Friday that U.S. ground troops were involved in gun battles with AQAP on Friday and were being supported by bombs from U.S. fighters. Davis said this was not the case. He also denied U.S. troops played any role in directing or coordinating the airstrikes.

While battlefield commanders have the authority to approve airstrikes in active war zones such as Iraq and Syria, actions in countries without a large U.S. military presence, such as Yemen, had required approval from the president.

The Pentagon did not disclose the extent of the new athorities in order to preserve the element of surpise.

"I don't want to tip our hand too much on what these authorities are, because in doing so that will allow our enemy to know what might be coming as well," Davis said.

"Our goal is for enemy to be surprised and caught off guard and that is what we have achieved in the past couple of nights with these strikes."