Moscow, Istanbul: Russia began retaliating for the downing of one of its warplanes by Turkey, whose president made conciliatory gestures while reiterating that his military would do the same again if its airspace was violated.

Turkey hasn’t apologised for its “treacherous stab in the back” or offered compensation after shooting down the jet, President Vladimir Putin said Thursday in Moscow at a meeting with new ambassadors to Russia. “It seems that the Turkish government is deliberately pushing Russian-Turkish relations into deadlock. We regret that.”

Russia announced that agricultural products from Turkey will be subjected to additional border checks and laboratory controls, saying that 15 per cent of Turkish goods were found to breach Russian safety requirements. Turkish transport groups reported that hundreds of trucks were being held up at the Russian border.

Signaling an imminent escalation, Prime Minister Dmitry Medvedev said Russia would prepare more economic measures within two days that could affect flights, trade and investment.

Turkey would give the same response today in the event of a further violation, said President Recep Tayyip Erdogan. Still, the Turkish military in no way targeted Russia in downing the fighter plane and wasn’t aware of its nationality until after the clash.

Turkey is “taking pains to secure peace and stability in the region, not to incite new tensions,” Erdogan said. “Our disagreeing with Russia about Syria policy is one thing, applying our rules of engagement is another.”

Erdogan condemned Putin’s claims that Turkey buys oil from Daesh as “slander,” urging the Russian leader to look closer to home for those helping fund the group.

Russia said its actions didn’t amount to an embargo on Turkish products. Controls on goods are being tightened amid an increased risk of extremism, Kremlin spokesman Dmitry Peskov told reporters on a conference call Thursday.

In Riyadh, meanwhile, Saudi foreign minister Adel Al Jubeir said on Thursday that a military option in Syria was still viable and support for the opposition fighting to oust President Bashar Al Assad would continue.

Al Jubeir also said Riyadh was in contact with various Syrian opposition groups about a potential meeting in the kingdom to unify their position ahead of upcoming peace talks in Vienna.

“If it (the conference) happens, its aim will be to unify the Syrian opposition and help them to come out with one vision so that it can play an active role in the talks to reach a peaceful solution that leads to the removal of Bashar Al Assad,” he added.