Frustrated Trump pressures advisers to explain why Cuba hasn't surrendered yet

President Donald Trump is growing impatient with the Cuban government's ability to hold onto power despite a U.S. pressure campaign.

The 79-year-old president has been pressing his advisers to explain why his administration's efforts to force the regime into collapse has not yet worked despite months of sustained economic pressure, reported NBC News.

" White House officials believe the regime could still fall by the end of this year without military intervention, but Trump has found that timeline insufficient," the network reported, based on three sources. "In response to the president’s frustrations, the Defense Department began updating plans for possible action."

The Pentagon has responded to Trump's frustration by updating plans for a possible military action against Cuba in case the president's orders an attack, according to two U.S. officials and a former official.

The Cuban government has given no indication they're willing to give up power or offer concessions despite U.S. sanctions and military action against Venezuela at the start of this year.

The White House responded to a request for comment by pointing to Secretary of State Marco Rubio's comments faulting Cuba for rejecting $100 million humanitarian aid offered by the U.S.

Rubio also stated that it is “an unacceptable status quo” that the U.S. has “90 miles from our shores a failed state that also happens to be friendly territory for some of our adversaries.”

The Defense Department revises operation plans on a rolling basis to prepare for various scenarios, NBC pointed out in its report.