Turkey on Saturday warned its citizens off non-urgent travel to Russia in the latest tit-for-tat move as the two nations square off over Ankara's downing of one of Moscow's warplanes.

The foreign ministry in Ankara said travel to Russia should be avoided a day after Moscow -- which had earlier urged its nationals to leave Turkey -- announced it was scrapping its visa-free regime for Turkish visitors.

The Russian government has in addition said it is preparing a raft of retaliatory economic measures to Tuesday's downing of its jet on the Turkey-Syria border -- that could see major investment projects and key economic sectors hit.

The incident has sparked a bitter war of words between the two strongmen leaders, Turkey's Recep Tayyip Erdogan and Russia's Vladimir Putin, who are rival players in the war in Syria.

NATO member Turkey blasted the Russian jet out of the sky after claiming it crossed into its airspace but Putin has furiously denied that and demanded an apology.

"We advise Russia not to play with fire," Erdogan said in a speech in Ankara on Friday, lashing out at Russia's response to the downing as well as its support of the regime of Syrian President Bashar al-Assad.

The shooting down of the jet is thought to be the first downing of a Russian warplane by a NATO member since 1952 and has been decried by Putin as a "stab in the back committed by accomplices of terrorists".

Erdogan has nevertheless said he wanted a direct meeting with Putin when the two leaders are in Paris next week for the UN climate summit.

But Putin is yet to agree to talks and Moscow has refused to let up the pressure on Ankara.

"From our point of view, it is now difficult to determine the level of predictability in the actions of the Turkish leadership," Kremlin spokesman Dmitry Peskov said in an interview released Saturday.

- Travel warnings, visas back -

The downing of the jet has seen limited anti-Turkish demonstrations in Russia and Turkish nationals in the country reportedly face increased checks from officials.

Citing problems faced by Turks in Russia in the wake of the incident the foreign ministry said non-urgent visits to Russia should be avoided "until the situation becomes clear."

Moscow has ruled out any military response, but has pledged broad measures targeting entire sectors of the Turkish economy including tourism, agriculture and possibly key energy projects.

Russian Foreign Minister Sergei Lavrov on Friday said Turkish nationals would require visas from January 1, after Putin this week warned citizens not to travel to Turkey -- a hugely popular destination for Russians.

Prime Minister Dmitry Medvedev on Thursday gave ministers two days to work out a plan to curb cooperation with Turkish companies after Russia said it would tighten checks on food imports over alleged safety standard violations.

Moscow has also hinted the reprisals could hit two major projects with Turkey -- a planned gas pipeline and a nuclear power plant.

The two countries have built trade ties in recent years and Russia is already energy-poor Turkey's biggest oil and gas supplier.

But they are on opposing sides in the Syrian conflict, with Ankara backing rebels fighting to topple Assad while Moscow is one of his last remaining allies.

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