Russian Federation Council Chairwoman Valentina Matviyenko said on Tuesday that President Recep Tayyip Erdoğan's letter to President Vladimir Putin expressing regret for Turkey's downing of the Russian military jet in November 2015, might form the basis for a thaw in relations between the two countries.

On Monday, Presidential spokesman İbrahim Kalın said in a statement that Erdoğan sent a letter to Putin to express his regrets about the downing of the Russian warplane and expressed condolences to the family of the Russian pilot who was shot dead in the incident.

''In the letter, the president wrote that he 'would like to inform the family of the deceased Russian pilot that I share their pain and to offer my condolences to them. May they excuse us,' " the statement read, and added that Erdoğan urged Putin to restore the previous friendly relations between the two countries.

The first response to Erdoğan's letter came from Matviyenko, who said that relations had gone through a "negative process" since the downing of the jet and the previously established sense of confidence was lost. But she added: "Still, this may become the basis for a thaw in relations between Russia and Turkey." Viktor Ozerov, the head of the defense committee of Russia's upper house of parliament, the Federation Council, had said in an interview in Moscow the day prior that the letter was Turkey's "first step" regarding improvement of bilateral relations.

Relations between the two countries hit a low in November 2015 after Turkish jets downed a Russian Su-24 bomber near the Syrian border for violating Turkish airspace. Turkey provided radar data that Russian planes breached the border while Moscow insisted that the warplane had not strayed from Syria.

At first, Erdoğan and Putin exchanged harsh criticism and ultimatums in the wake of the jet crisis. The Kremlin directed accusations at Ankara and imposed sanctions that continue to deal a heavy blow to Turkey's tourism sector. Russia's sanctions hit itself as well. Due to sanctions imposed on Turkish goods, vegetable and fruit prices in Russia have risen.

In the fallout after Turkey shot down the Russian jet, Moscow announced several wide-ranging sanctions on Turkey starting in January, including the end of visa-free travel and a ban on Turkish food products. Russia also called for its nationals to boycott Turkey as a tourist destination.