Vladimir Putin has issued a furious new attack on the government of Turkey over the shooting down of a Russian warplane, using crude language and saying it may be impossible to heal the relationship between the two countries.

The Russian president was answering questions from journalists at a marathon Q and A session to mark the end of the year, lasting just over three hours and involving almost 1,400 reporters in a vast Moscow conference centre.

Mr Putin gave his strongest confirmation yet of Russian military involvement in east Ukraine, admitting specialist intelligence officers carrying out “certain tasks” were deployed to the region.

But he reserved his strongest statement for Turkey, who he accused of carrying out “a hostile act” when it destroyed a Russian Su-24 bomber on the Turkish-Syrian border in late November.

“The Turks,” he said, “decided to lick the Americans in a certain place.”

Russia has since imposed strong economic sanctions of Turkey in retaliation for the incident, and positioned its most advanced anti-air weaponry to bases in northern Syria.

And asked if he foresaw a thawing of relations in future, Mr Putin said: “It is hard for us to reach agreement with the current Turkish leadership, if at all possible.

Russian plane shot down by Turkish jets Show all 5 1 /5 Russian plane shot down by Turkish jets Russian plane shot down by Turkish jets Russian aircraft goes down in Kizildag region of Turkey's Hatay province, close to the Syrian border Russian plane shot down by Turkish jets Russian aircraft goes down in Kizildag region of Turkey's Hatay province, close to the Syrian border Russian plane shot down by Turkish jets Russian aircraft goes down in Kizildag region of Turkey's Hatay province, close to the Syrian border Russian plane shot down by Turkish jets Russian aircraft goes down in Kizildag region of Turkey's Hatay province, close to the Syrian border Russian plane shot down by Turkish jets Russian aircraft goes down in Kizildag region of Turkey's Hatay province, close to the Syrian border

“What have they achieved? Maybe, they thought that we would run away from there (Syria)? But Russia is not such a country,” he said.

On Ukraine, Russia has never accepted accusations from Washington and others that its army has been involved in fighting to bolster rebels in the disputed Donbass region.

Journalists put to him the fact that two Russian military spies had been captured by Ukrainian government forces and put on trial in Kiev.

“We never said there were not people there who carried out certain tasks including in the military sphere,” he said, insisting this was not the same as deploying regular Russian troops.

Mr Putin used the start of the conference to address affairs at home, reassuring domestic viewers on the troubled state of the Russian economy and falling oil prices.

“The Russian economy has passed the crisis. At least, the peak of the crisis,” Mr Putin said.

The Christmas conference, a set piece of the Russian political calendar, came as Mr Putin’s own approval ratings hit 85 per cent positive – not far off the record high of almost 90 per cent in October.