Geneva - Syria has given approval for humanitarian convoys to reach all of the country's 19 besieged areas by the end of this month, but warned that "approval... does not mean delivery," the UN said on Thursday."We were informed by our team in Damascus that basically there has been a permission, an approval... by the government of Syria for all 19 besieged areas," the UN's envoy to Syria, Staffan de Mistura, told reporters. He stressed that Syria has given such approvals in the past before ultimately blocking convoys from distributing life-saving supplies. He made the comments after the weekly meeting of the Syria humanitarian task force, co-chaired by the US and Russia, which has for months been trying to boost aid supplies to millions of Syrians in need. That task force has faced pressure, including from France and Britain, to start air-dropping aid into besieged areas, with Syrian President Bashar Assad's military continuing to block road convoys. De Mistura said "all options are on the table," voicing hope that a surge of road convoys in the coming weeks would make dangerous and costly air deliveries unnecessary.