The Trump administration has proposed spending 18 billion US Dollar over 10 years to significantly extend the border wall with Mexico. According to a US official, the proposal by Customs and Border Protection calls for 505 kilometres of the additional barrier by September 2027, bringing total coverage to 1,552 kilometres, or nearly half the border. <br/><br/>The official said it also calls for 651 kilometres of replacement or secondary fencing. Trump has promised "a big, beautiful wall" with Mexico as a centrepiece of his presidency but offered few details of where it would be built, when and at what cost. <br/><br/>His administration asked for 1.6 billion dollars this year to build or replace 118 kilometres of fencing in Texas and California, and officials have said they will also seek 1.6 billion dollars next year.<br/><br/>