Russia on Wednesday said it has the right to make military recourse to the downing of its warplane earlier this week by NATO member Turkey. "This is intentional murder of our soldiers and this deed must be punished," chairman of the Duma, the lower house of parliament, Sergei Naryshkin said on Friday.
In an interview with Romanian television station Digi24, Naryshkin, who spoke in Russian and was translated by the broadcaster, said: "We know those who did this and they must be judged. At the same time, the response from the Russian side will surely follow, in line with international law.
''And, aside from this, Russia has also the right to military response," added Naryshkin.
He was attending a meeting of the Parliamentary Assembly of the Black Sea Economic Cooperation (PABSEC) in Bucharest.
The shooting down of the Russian warplane 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 Islamic State militants.
Russia also alleged collusion between the government in Turkey led by President Tayyip Erdogan and the Islamic State militants to carry on illegal oil trade and in restricting the Kurdish fighters from Syria.
Russia's defence ministry on Wednesday said it had proof that Turkish President Tayyip Erdogan and his family were benefiting from smuggling of oil from Islamic State-held territory in Syria and Iraq.
Russian defence ministry also showed satellite images of columns of tanker trucks loading oil at stations controlled by Islamic State in Syria and Iraq and crossing into Iraq, although it did not explain how Erdogen and his kin benefitted from the illegal smuggling.
Naryshkin, who said economic measures against Turkey might be on the cards, said Moscow had allocated additional military resources on Thursday to boost the security of Russian warplanes.
"Even yesterday, military resources were allocated, (for) the S400 Triumph, which is the most advanced missile defence system, with the role to maintain flight safety of Russian planes, of our military and air forces whose task is to destroy terrorist infrastructure of the so-called Islamic State and other organisations operating in Syria."
Moscow and Ankara have been locked in a war of words since last week's shooting down of a Russian warplane by a Turkish air force jet near the Syrian-Turkish border, the most serious incident between Russia and a NATO state since the stand-off over Cuba half a century ago.
On Thursday, Turkish President Tayyip Erdogan was quoted as saying, Russia should apologise for violating Turkey's airspace.
Erdogan also called Moscow's accusations of Turkey buying oil from Islamic State as "slander" and said he would stand down if such allegations were proven to be true. But he also said he did not want relations with Moscow to worsen further.
World leaders, including US President Barack Obama, have been urging both sides to avoid escalation.