"NASA should NOT be talking about going to the Moon - We did that 50 years ago," Donald Trump tweeted

President Donald Trump on Friday criticized NASA for promoting its plan to return to the moon before human exploration of Mars, a strategy that Trump endorsed in a directive early in his tenure and championed as recently as last month.

"For all of the money we are spending, NASA should NOT be talking about going to the Moon - We did that 50 years ago," Trump said on Twitter. "They should be focused on the much bigger things we are doing, including Mars (of which the Moon is a part), Defense and Science!"

The tweet, sent from Air Force One as Trump returned from a trip to Europe, did not make clear whether he thinks the strategy should be entirely abandoned or whether he was more concerned about how NASA was branding the strategy.

A White House official sought to downplay any difference between what Trump had tweeted and existing policy.

"Our Administration's goal has always been to get to Mars," said the official, who was not authorized to speak publicly and requested anonymity, in an email. "We have asked Congress for additional resources to get to the Moon by 2024, which will enable us to get to Mars roughly a decade after creating a sustainable presence on the lunar surface. Under POTUS, America is leading again in space."

A tweet later Friday by NASA Administrator Jim Bridenstine did little to clarify the impact of Trump's tweet.

"As @POTUS said, @NASA is using the Moon to send humans to Mars!" the tweet said. "Right now, @MarsCuriosity and @NASAInSight are on Mars and will soon be joined by the Mars 2020 rover and the Mars helicopter."

Trump's tweet was sent shortly after Fox Business host Neil Cavuto questioned on air why NASA is "refocusing on the moon, the next sort of quest, if you will" and asked: "But didn't we do this moon thing quite a few decades ago?"

The policy of first going back to the moon grew from a unanimous recommendation by the new National Space Council, chaired by Vice President Pence, after its first meeting in October 2017.

At a ceremony where Trump signed a directive regarding the policy two months later, he said first returning to the moon would "establish a foundation for an eventual mission to Mars, and perhaps someday, to many worlds beyond."

In a tweet three weeks ago, Trump touted his administration's commitment to space exploration, writing: "Under my Administration, we are restoring @NASA to greatness and we are going back to the Moon, then Mars."

In a fiery speech in March, Pence announced that NASA was moving its timeline for landing humans back on the moon up by four years, to 2024. He cast the mission as part of a new space race against superpowers such as Russia and China, which landed a spacecraft on the far side of the moon earlier this year.

In public documents, NASA has argued that "exploration of the Moon and Mars is intertwined."

"The Moon provides an opportunity to test new tools, instruments and equipment that could be used on Mars, including human habitats, life support systems, and technologies and practices that could help us build self-sustaining outposts away from Earth," the agency says in one document available on its website.