The condition of Mohammed Allan is being closely monitored by opposing forces in an Israeli-Palestinian conflict.
The North Africa nation has been under a UN arms embargo since 2011, which was renewed in March, but some exemptions have been allowed.
Government planes launched dozens of air strikes overnight into the morning on parts of the Sahl Al Ghab plain seized by rebels in an advance this month.
Over 80 killed in battle for Yemeni city of Taez
Bodies of 50 rebels and allied fighters were recovered from Taez while 31 pro-government fighters had been killed.