US Defence Secretary Leon Panetta Wednesday expressed concern over the chemical and biological weapons in Syria and said the US is working with regional countries in monitoring them so that those weapons do not fall in wrong hands. He told a press conference in Brussels after the end of a 2-day NATO defence ministers meeting that the US is working with its allies in the region to apply as much pressure as possible for Bashar Al Assad to step down. \"The US has been working with Jordan on developments related with Syria on humanitarian needs, the refugee flow and also to monitor the CBW (chemical and biological weapons) sites in Syria and how best to respond,\" he said . He said the US is working with Jordan also to develop their operational capabilities \"in the event of any contingency.\" Panetta said the US is also in contact with Turkey to provide any assistance they need . He said the US is operating in three areas regarding Syria, humanitarian aid, cooperating with regional states and thirdly in supporting the opposition. \"We are monitoring the CBW sites in Syria . We continue to be concerned about security of those sites. We want to make sure that security is maintained and that those weapons do not fall into the wrong hands,\" he stressed. \" We have been providing non-lethal support to the opposition and we know there are countries in the region that are supplying lethal support but our effort is aimed at working with the opposition in every way possible to assist them in the effort to try to develop their capabilities,\" said the US defence secretary.