Russia said on Friday the Syrian plane intercepted by Turkey on a flight from Moscow was carrying a cargo of dual-purpose radar equipment but insisted that Moscow did not violate any laws.
"This cargo is electrical technical equipment for radar stations, this is dual-purpose equipment but is not forbidden by any international conventions," Foreign Minister Sergei Lavrov said in the Russian government's first public remarks about the nature of the cargo.
"We have no secrets."
"The plane contained cargo that a legal Russian supplier delivered legally to a legal client," Lavrov said in remarks posted on the Kremlin website, speaking after a meeting of the Russian security council chaired by President Vladimir Putin.
"There were no weapons on board this plane, nor could there have been."
The Kremlin said the council meeting discussed the situation in Syria, among other issues.
"Using passenger planes to transport such types of cargo is absolutely common practice which is also confirmed by the fact that before the Syrian plane entered Turkish airspace, Turkey's authorities offered it to either change its route or land in Ankara," Lavrov said.
"The pilot made a landing because he knew he was not doing anything illegal.
"According to our data, the supplier will demand that the cargo, which is its property, be returned," added the foreign minister.
Lavrov's confirmation that the plane was carrying sensitive cargo to conflict-torn Syria came after the respected Kommersant newspaper reported that the plane was carrying Russian radar parts for Syrian missile defence systems but not weapons.
The plane was loaded with 12 boxes containing parts for radars used in the Syrian army's missile defence systems, Kommersant quoted sources in the arms export industry as saying, denying accusations by Turkish Prime Minister Recep Tayyip Erdogan that the cargo included ammunition.
The sources told the paper that the cargo needed no special documentation as it posed no risk to the crew of the plane or the aircraft itself.
"This is not a weapon. If a person takes a radio receiver that has been switched off onto the plane then does this pose a threat for the airliner or the passengers?" asked the source.
"No international laws were violated."
The spokesman of Russia's weapons export agency Rosoboronexport Vyacheslav Davidenko denied "there was any cargo belonging to us" on the plane, as Erdogan had implied.
The SyrianAir plane flying from Moscow to Damascus was forced to land at Ankara's Esenboga airport by the Turkish air force on Wednesday.
The plane was later allowed to continue to Damascus but Turkey has held on to what it deemed to be suspect cargo.
Erdogan said the plane was carrying "equipment and ammunition" destined for the Syrian defence ministry that had apparently been provided by Rosoboronexport.
The incident has not only raised tensions between Turkey and the Syrian government -- already at bitter odds -- but also hurting ties between Ankara and Moscow which have starkly differing views on the Syria conflict.