Acting Border Patrol Chief Carla Provost testified in a congressional appropriations hearing Tuesday that border wall construction will likely begin in March or April 2018.

The Trump administration’s budget request for Fiscal Year 2018 includes $1.6 billion to go towards border wall construction. This funds 60 miles of new border walling, and would replace 14 miles of existing fencing.

Provost told the House Committee on Appropriations that a priority for the Border Patrol is fixing insufficient fencing in San Diego that has been used by “transnational criminal organizations.” The federal government is currently in the prototype stage of building the southern border wall President Trump ordered to be constructed.

The four to eight prototypes will be constructed in the San Diego area, and Provost said the current timeframe for this to take place is sometime in “late summer.” She went on to say that if Customs and Border Protection receives the $1.6 billion it has requested, the goal is to start constructing border walls in the Rio Grande valley in March or April 2018.

The acting Border Patrol chief said that this area has been exploited by “bad actors,” and is “lacking infrastructure” to stop this. Provost also testified that border walling is not necessary along all 1,900 miles as natural barriers, such as the Big Bend National Park, exist.

The Trump administration has yet to build the border wall on which the president campaigned on constructing, and some immigration hawks such as conservative commentator Ann Coulter and Iowa Rep. Steve King aren’t pleased.

King told The Daily Caller recently that he is trying to get more funding for border wall construction in the Fiscal Year 2018 budget.