Balloons with a poster reading "drop dead damned prostitute!" fly outside the Turkish embassy in Moscow. Credit:AP At a cabinet meeting, Mr Medvedev said that joint investment projects with Turkey would be frozen or cancelled. Negotiations over a proposed preferential trade regime with Turkey would also be scrapped, he said. Mr Medvedev called for recommendations from government agencies to be submitted within two days. "These documents will introduce restrictions and bans on the activity of Turkish economic structures in Russia, limiting deliveries of goods, including foodstuffs, labour, and services from Turkish companies," Mr Medvedev said. Russian Economic Development Minister ​Alexei Ulyukayev at the same session said that economic sanctions would affect Turkstream, the planned gas pipeline from Russia to Turkey announced by Mr Putin last December, and the Akkuyu Nuclear Power Plant, Turkey's first nuclear power plant, which it signed an agreement with Russia to build in May 2010. He added that the sanctions may affect direct flights between Russia and Turkey.

Elsewhere, government agencies were busy. Rospotrebnadzor, Russia's consumer oversight agency, announced it had seized 800 kilograms of "high-risk Turkish products", including meat, sweets and nuts. And in the southern Kuban region, Russia's Migration Service said it had arrested and would deport 39 Turkish businessmen who attended an agricultural expo on tourist visas. Analysts say that Russia will choose from a menu of asymmetric responses in retaliation against Turkey, including informal economic sanctions and providing military aid to Turkey's enemies, including the Kurds. "The consequences are going to be significant," said Fyodor Lukyanov, a prominent Russian political analyst. Russia probably would not scale back its deployment in Syria because of the incident, he added. The Russian Defence Ministry announced in a statement on Wednesday that Russian fighter jets will now escort the bombers launching air strikes in Syria. On Thursday, Moscow said it had already deployed powerful S-400 ground-to-air missiles that can reach across the country and far into Turkey from the Russian airbase in the province of Latakia on Syria's Mediterranean coast.

The incident has revealed the potential for conflict between foreign powers supporting and opposing Syrian President Bashar al-Assad despite a shared opposition to Islamic State. In particular, Russian air strikes against Turkish-backed rebel groups have fomented deep frustration in Ankara. "There is a clear message from the Turks with this downing of a Russian jet," Mustafa Alani, a Middle East expert at the Geneva-based Gulf Research Centre, said. "It is a check on Russia's policy in the region. Russia can't do whatever it wants." Russia is unlikely to change its mission in Syria as a result, Russian analysts said, and will seek to punish Turkey on the ground there. "Of course, Russia is going to intensify strikes on that part of Syria and on those groups that are affiliated with Turkey," Mr Lukyanov said. On Wednesday evening, Turkey's state-run news agency, Anadolu, reported that Russian air strikes targeted Turkish aid vehicles in the Syrian border town of Azzaz, killing at least seven drivers. The town is a hub for supplies being delivered from Turkey to Syrian rebels fighting government forces in the nearby city of Aleppo. The details of the incident could not be assessed independently.

On Thursday morning, reports emerged of a second bombing raid against Azzaz. Shady al-Ouaineh, a media representative for Determined Storm, a rebel group associated with the Free Syrian Army, said in a telephone interview that Russia had dramatically intensified air raids in the rebel-held areas of Latakia province. Syrian government forces and allied Shiite militiamen from Iraq, backed by Russian air cover, have been trying to advance on some of the last opposition holdouts in the province, Mr Ouaineh said, close to where the Russian jet was shot down. "It is clear Russia is taking out its revenge on us here," he said. Russian attitudes towards Turkey, which were reasonably friendly a year ago, have turned cold with alarming speed. Most Russian tour operators stopped selling travel packages to Turkey on Wednesday. Protesters in Moscow pelted the Turkish embassy with eggs and rocks, shattering windows. Russian legislators introduced a bill that would criminalise denying that the mass killings of Armenians in 1915 by the Ottoman Empire was a "genocide". The issue remains highly sensitive: Turkey acknowledges that atrocities occurred but has long denied that what took place constituted a genocide.

Russia will seek retribution against Turkey but wants to avoid antagonising the West, Alexander Baunov, an analyst at the Moscow Carnegie Centre, said. "If this becomes a fight between Russia and the West, then that goes against the goals of the intervention in the first place: to escape international isolation connected to sanctions," he said. Those sanctions were imposed after Russia annexed the Crimean Peninsula and backed separatist rebels in Ukraine's south-east. US President Barack Obama at a meeting with French President Francois Hollande in Washington on Tuesday, said that Turkey had a right to defend its airspace and accused Russia of attacking moderate opposition groups as opposed to IS. Russia has said it carries out air strikes only against terrorist organisations. "They are operating very close to a Turkish border and they are going after a moderate opposition that are supported by not only Turkey but a wide range of countries," Mr Obama said. At the same time he discouraged "any kind of escalation". Mr Putin has promised the Russian public a limited engagement in Syria, with no ground forces, to limit casualties. Although the Syrian army has managed to halt a rebel offensive, Russian air power has not yet led to a significant turn of the tide in the war.

"Turkey dealt a major blow to Putin, and now he's been placed between a rock and a hard place," Fawaz Gerges, a professor of international relations at the London School of Economics, said. "There could be mission creep where Russia will get entangled in an unwinnable war." The Washington Post Follow FairfaxForeign on Twitter Follow FairfaxForeign on Facebook