The Trump administration is requesting $18B from Congress to build a 700-mile U.S.-Mexico border wall.

The wall would be completed over 10 years and is expected to cost a total of $9B in the first half of the decade and $8.7B in the second, the Wall Street Journal reports. In May, President Donald Trump asked Congress for $1.6B to build and replace 74 miles of barriers. At the time, the wall was estimated to cost $22B total. This number is now anticipated to be closer to $33B when including security measures, technology and personnel.

Should Congress agree, the new wall would expand on the current 654-mile barrier separating Mexico and the U.S. When completed in 2027, the wall would be more than 1,000 miles long, covering almost half of the southwest border.

The request comes at a time when lawmakers and the White House are cracking down on illegal immigration and debating the future of policies such as the Dream Act, which  involves children of undocumented immigrants who were brought to the U.S. by their parents.