Story highlights 'My administration is committed to keeping our air and water clean,' Trump said

The Trump administration has been criticized for proposing steep cuts to the EPA

(CNN) President Donald Trump declared his support for the environment and scientific research on his first Earth Day in the White House amid harsh criticisms over his actions to roll back environmental regulations and proposed cuts to non-military spending, including at the Environmental Protection Agency.

"Rigorous science is critical to my administration's efforts to achieve the twin goals of economic growth and environmental protection," Trump said in a statement Saturday as thousands of marchers filled the streets of downtown Washington to support science and evidence-based research -- a protest partly fueled by opposition to Trump's threats of budget cuts to agencies funding scientists' work.

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"My administration is committed to advancing scientific research that leads to a better understanding of our environment and of environmental risks," Trump said. "As we do so, we should remember that rigorous science depends not on ideology, but on a spirit of honest inquiry and robust debate.

"This April 22nd, as we observe Earth Day, I hope that our nation can come together to give thanks for the land we all love and call home," Trump added.

In a tweet later Saturday, however, Trump stated that while he is "committed" to environmental protection, people shouldn't forget that "jobs matter."