Two senior US officials have described widespread opposition within the Trump administration

The comments from the current and former officials come hours after Trump, in a series of tweets on Saturday, threatened to attack 52 Iranian sites -- including cultural ones -- should the country respond with military force to a US strike in Iraq last week that killed Iranian military commander Qasem Soleimani and several others.

The pointed threat by the President has been met with criticism as it's highly unusual for the US to target cultural rather than military sites, with some critics suggesting such action may violate international law.

Among those critics was Colin Kahl, former deputy assistant to President Barack Obama and national security adviser to Vice President Joe Biden, who tweeted on Saturday that targeting such sites would be "a war crime" and that he finds it "hard to believe the Pentagon would provide Trump targeting options that include" them.

The White House did not return a request for comment Saturday evening for details regarding the President's tweet. CNN has asked for comment on Sunday regarding the opposition within the administration.

Secretary of State Mike Pompeo on Sunday defended Trump's Twitter threat, arguing during an interview on CNN's "State of the Union" that such an action would not violate international law and instead suggested it would be a continuation of the administration's attempt at deterrence and defense.

"If we need to defend American interests, we will do so. What President Trump said last night is consistent with what we have said all along," he told CNN's Jake Tapper.

"And the American people should know we will always defend them and we'll do so in a way that is consistent with international rule of law and the American Constitution," Pompeo said, insisting when facing pushback from Tapper that strikes against Iranian cultural sites and an action consistent with international law are "not two different things."