Moscow lends Turkey credit card to buy Russian missiles
The loan required to buy a new S-400 missile system was being considered by the Kremlin, Russia's state-owned news channel, Rossiya-24.
"They have expressed a wish to get a loan, but the issue has not yet been resolved," the CEO of Rostech said.
"The Finance Ministry is holding talks, as soon as they sign this and take a decision on allocating a loan, we will sign contracts on supplies, including the S-400."
Turkey's President Erdogan met with Russia's President Putin in Moscow last week to discuss a number of bilateral agreements - including a purchase order on the anti-aircraft missiles.
The deal is considered controversial because Turkey is a NATO member - a military defence organisation that Russia is not party to.
One of the S-400 system's main strengths is its mobility, as the missiles are positioned on the back of a truck.
Russia has reportedly deployed a number of S-400 missiles to Syria to enforce a no-fly zone around its deployment base there.
One of the latest customers for Russia's missile defence systems was Iran, who bought the S-300 system - the model down from the S-400 - the week previous to Erdogan's visit.