WASHINGTON – House Democrats will initiate action Friday to try to block President Donald Trump's declaration of an emergency along the southern border.

Trump announced the declaration last week as a means of freeing up billions to pay for his proposed wall along the U.S.-Mexico border after Congress failed to give him the money he demanded.

Democrats have called the declaration an overreach of Trump's power and have vowed to fight it but on Wednesday, they laid out their plans.

According to a letter sent by Democratic Rep. Joaquin Castro's office, the Texas Democrat will introduce a resolution Friday morning that, if passed by both the House and Senate, would terminate the emergency declaration.

A copy of the one-page resolution was sent out by House Speaker Nancy Pelosi late Wednesday to others in the House, where she urged members to join in backing the move. She said the House "will move swiftly to pass the bill" and vowed to have it move quickly through committees so that Congress could vote on the measure.

"All Members take an oath of office to support and defend the Constitution," Pelosi said in her letter. "The President’s decision to go outside the bounds of the law to try to get what he failed to achieve in the constitutional legislative process violates the Constitution and must be terminated. We have a solemn responsibility to uphold the Constitution, and defend our system of checks and balances against the President’s assault."

The resolution is likely to have strong support in the Democratic-led House. But it faces a tough fight after it's passed to the Republican-controlled Senate.

Many Republicans have said they were uncomfortable with the president declaring a national emergency to get funding for a wall along the southern border but it's unclear whether they would vote for such an effort.

Trump made the emergency declaration after Congress allocated $1.375 billion for a barrier along the southern border, far short of the $5.7 billion Trump had demanded. The fight over wall funding led to a 35-day government shutdown – the longest on record.

White House officials have said the emergency declaration and other budget maneuvers would free up an additional $6.6 billion, which would build at least 234 miles of border wall.

Along with Congress moving to void the order, the move has also drawn as number of legal challenges in court.

Sixteen states already filed a lawsuit over Trump's emergency declaration, arguing it exceeds the power of the president and unconstitutionally redirects federal money that Congress had set aside for other purposes.