MOSCOW — Russia threatened economic retaliation against Turkey on Thursday and said it was still awaiting a reasonable explanation for the shooting down of its warplane.

Turkey dismissed the threats as "emotional" and "unfitting." President Tayyip Erdogan also told CNN that Russia, not Turkey, should be the one to apologize for the incident.

The shooting down of the jet by the Turkish air force on Tuesday was one of the most serious clashes between a NATO member and Russia, and further complicated international efforts to battle ISIS militants.

The Russian warplane was shot down near the Turkish-Syrian border on Tuesday. HaberTurk TV / EPA

World leaders have urged both sides to avoid escalation.

Earlier, Russian Prime Minister Dmitry Medvedev ordered his government to draw up measures that would include freezing some joint investment projects and restricting food imports from Turkey.

Economy Minister Alexei Ulyukayev said Moscow could put limits on flights to and from Turkey, halt preparations for a joint free trade zone, and restrict high-profile projects including the TurkStream gas pipeline and a $20 billion nuclear power plant Russia is building in Turkey.

Russia's defense ministry meanwhile said it had suspended all cooperation with the Turkish military, including a hotline set up to share information on Russian airstrikes in Syria, the TASS news agency reported.

Kremlin spokesman Dmitry Peskov said Russia was still awaiting a reasonable answer from Ankara on why it downed the fighter jet. Moscow insists it never left Syrian air space, but Ankara says it crossed the border despite repeated warnings.

Erdogan said the Russian jet was shot down as an "automatic reaction" to the violation of Turkish air space, in line with standing orders given to the military.

The head of Russia's tourism agency, Rostourism, said cooperation with Turkey would "obviously" be halted. At least two large Russian tour operators had already said they would stop selling packages to Turkey after Russian officials advised tourists against traveling to its resorts.

Related: Why Downing of Russian Jet Won't Start World War III

Russians are second only to Germans in terms of the numbers visiting Turkey, bringing in an estimated $4 billion a year in tourism revenues, which Turkey needs to help fund its gaping current account deficit.

Medvedev said Russia may impose restrictions on food imports within days, having already increased checks of Turkish agriculture products, its first public move to curb trade.

Moscow banned most Western food imports in 2014 when Western countries imposed sanctions on Russia over its role in the Ukraine crisis, leading to supply disruptions as retailers had to find new suppliers and galloping inflation.

The dispute has also put a brake on new wheat deals between Russia, one of the world's largest wheat exporters, and Turkey, the largest buyer of Russian wheat.