 Complete the following phrase:  In 2003, Saudi Arabia began construction of a border wall with Yemen citing organised smuggling and security concerns. Following international diplomatic pressure and accusations that this violated the 20km buffer zone reserved for grazing in the 2000 treaty, Saudi Arabia agreed to halt construction and both sides to uphold the treaty in February 2004. However, Saudi Arabia would subsequently complete the wall between 2009-2010. The border has become increasingly patrolled and crossings restricted following the destabilising effects of the 