Syria's air force has adapted the Mikoyan MiG-21 fighter to be flown unmanned and to carry chemical warfare materials, intelligence analysts have claimed.
On 21 June 2012, Syrian pilot Col Hassan Hamada took off in a MiG-21 from al-Dumair military airport, northeast of Damascus, and flew to King Hussein air base just across Syria's southern border with Jordan, before requesting political asylum.
Unlike in earlier defections, Syria put heavy pressure on Jordan to return the impounded aircraft. According to some sources, the fighter was found to have been fitted with a remote-control system, and with the capability to carry and dispense a "deadly volume" of chemical warfare agents.
Tal Inbar, a senior researcher at Israel's Fisher Institute for Air and Space, says such adaptations have previously been made in other countries, including Iraq, but notes that there is no hard evidence yet that Syria modified the aircraft to perform unmanned missions with chemical weapons.
The Israeli air force has recently expressed deep concern about the stockpile of chemical warfare materials held by Syrian president Bashar al-Assad's regime. The service's commander, Maj Gen Amir Eshel, says Syria is falling apart rapidly and the situation creates a host of security threats that are "very, very close to Israel".
"We don't know what will happen the day after Assad falls," he says. "We are preparing ourselves for this, and for the eventuality of weapons flowing out of Syria."
Eshel says preparations are being made to deal with the potential threats.
Sources claim the monitoring of Syrian bases in recent weeks has produced evidence that engineers have loaded chemicals, including the deadly nerve agent Sarin, into bombs that could be dropped by fighter aircraft. Observation satellites have also detected the movement of vehicles among bunkers where the weapons and agents are believed to be stored, the sources add.