AMMAN (Reuters) - Armored vehicles and a tank with a Russian flag were seen heading towards the Nasib border crossing between Jordan and Syria, several witnesses near the crossing said on Friday.

They said they spotted a convoy on a military road heading towards the crossing in rebel hands which the Syrian army has been advancing towards since Thursday.

Several thousand displaced civilians are congregating near the frontier area seeking shelter from heavy Russian aerial bombardment of their towns and villages in Deraa province.