????Photo taken on Oct. 21, 2015 shows Russian Sukhoi Su-24 taking off from the Hmeymim airbase in the Latakia province, Syria. The Russian Defense Ministry on Tuesday confirmed that a Su-24 warplane crashed in Syria. (Xinhua/Sputnik)

　　MOSCOW, Nov. 24 (Xinhua) -- Russia's Defense Ministry said on Tuesday that it is working on a set of measures in response to the downing of a Russian warplane by Turkey and similar incidents in future.

　　"Russia's Defense Ministry is currently working on a set of measures to react to such incidents," the ministry said in an online statement.

　　Earlier on Tuesday, Turkish fighters shot down the Russian Su-24 warplane after issuing numerous warnings about the plane's alleged violation of its airspace. However, Russia said the plane was shot down over Syria.

　　Terming the action of Turkish air forces as "unfriendly," the Defense Ministry said it had summoned Turkey's military attache in Moscow for an official protest.

　　Meanwhile, the attempts to establish hotline contacts with the Turkish side also failed, the ministry said, adding that the episode would not derail the ongoing Russia's air campaign against terrorist in Syria.

　　Kremlin spokesman Dmitry Peskov also confirmed that the incident would not affect Russia's anti-terrorist operations in Syria.

　　Following the shooting down of the Russia fighter jet, Turkey turned to NATO and requested to hold an emergency meeting to discuss the incident.

　　Peskov said that the Kremlin is waiting for the results of NATO extraordinary meeting on the incident to "see their assessment of these provocative and inadmissible actions of the Turkish side."

　　Russian President Vladimir Putin"was not talking about any military implications" in his statement made earlier on the issue, he added.

　　"There is no doubt that we should avoid any hasty and emotional reaction, but at the same time, it is clear that such actions will not be left without consequences," RIA Novosti news agency quoted Peskov as saying.

　　Before a meeting with King Abdullah II of Jordon in Sochi, Russia, Putin called the incident a "stab in the back" by those who "abet" terrorism and warned that it would have serious consequences for Russia-Turkey relations as "Russia would not tolerate crimes like what happened today."

　　In another development, Russian Foreign Minister Sergei Lavrov canceled his trip to Turkey originally planned on Wednesday.

　　"The president said openly that Russian-Turkish relations cannot be unaffected. In this context, it was decided to cancel the fifth session of the Joint Strategic Planning Group Meeting planned for Wednesday in Turkey's Istanbul at the level of Foreign Ministers of the Russian Federation and the Republic of Turkey," Lavrov said at a press conference.

　　The minister also suggested Russians scrap their trips to Turkey for tourism or any other aims, citing security concerns.

　　Local media reported that Russian Federal Tourism Agency recommended Russia's travel agents halt the promotion or sale of package tours to Turkey.

　　"We will make a request to the travel agencies to find out the number of Russian tourists in Turkey in order to be ready to implement any measures proposed by the Russian government," head of the agency Oleg Safonov was quoted by Tass.

　　A major tourist agency Natalie Tours, headquartered in Moscow, said in an online statement that it had cancelled booking tours to Turkey from all its offices in Russia, Ukraine, Kazakhstan and Belarus from Tuesday due to "unstable political situation and measures taken by the Russian state to guarantee its citizens' security."

　　Russians are the second largest tourist group visiting Turkey, according to official data. Nearly 4.5 million Russians visited Turkey last year, accounting for 12 percent of all tourists there.

　　A Russian Su-24 warplane was shut down over Syria near the Turkish border on Tuesday by Turkish air forces. Turkey said it had warned 10 times in five minutes about its violation of Turkish airspace.

　　However, Putin said Tuesday that the Russian plane was shot by a Turkish missile over Syria about 1 km away from the Turkish border and therefore did not violated Turkey's airspace.

　　Russian helicopters are searching for the two pilots near the Syrian border, while reports citing a Russian senior military official as saying one of the pilots was killed in midair by gunfire from the ground.

　　Sergei Rutskoy, chief of the Russian General Staff Main Operations Directorate, also confirmed that one soldier was killed during the rescue operation after a Mi-8 helicopter was downed by ground fire, according to RIA Novosti news agency.