Story highlights "I will not be moved. The President must be impeached," Rep. Al Green said

Rep. Al Green is one of several members who have used the word "impeachment"

Washington (CNN) Democratic Rep. Al Green of Texas called for the impeachment of President Donald Trump Wednesday morning, the first member of Congress to officially request leveling charges against the President from the House floor.

"This is about my position. This is about what I believe. And this is where I stand. I will not be moved. The President must be impeached," Green said on the floor. "For those who do not know, impeachment does not mean that the President would be found guilty. It simply means that the House of Representatives will bring charges against the President. It's similar to an indictment but not quite the same thing."

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Green, who previewed his call with a tweet earlier, said it was the House of Representative's "duty" to take up impeachment.

News broke Tuesday that Trump in February asked then-FBI Director James Comey to drop an investigation into his former national security adviser Michael Flynn -- a request critics have called obstruction of justice.

As the backlash escalates to Trump's firing of Comey last week, Democratic lawmakers are increasingly raising the prospect of impeachment.

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