Syria crisis: Obama warns chemical arms use a 'game changer'
26 April 2013 Last updated at 23:03 BST
US President Barack Obama has vowed a "vigorous investigation" into reports Syria has used chemical weapons, warning they will be a "game changer" for US policy if proven true.
Mr Obama was speaking as he met King Abdullah II of Jordan at the White House following emerging evidence that Syria has used weapons such as the nerve gas sarin.
He said: "Horrific as it is when mortars are being fired on civilians and people are being indiscriminately killed, to use potential weapons of mass destruction on civilian populations crosses another line with respect to international norms and international law."