By Orhan Coskun, Ece Toksabay and Huseyin Hayatsever
ANKARA (Reuters) -Kemal Kilicdaroglu, main challenger of Turkish President Tayyip Erdogan, said on Friday his party has concrete evidence of Russia's responsibility for the release of "deep fake" online content ahead of Sunday's presidential elections.
Kilicdaroglu, who has a slight poll lead over Erdogan two days ahead of the election, told Reuters in an interview it was unacceptable for Russia to interfere in Turkey's internal affairs, but added that should he become president he would maintain Ankara's good ties with Moscow.
NATO-member Turkey depends heavily on energy imports and Russia is its largest supplier. This week, two sources told Reuters that Ankara has deferred payment to Russia of a $600 million natural gas bill to 2024, underlining the extent of strengthened relations under Erdogan and Russian President Vladimir Putin.
Asked why he tweeted on Thursday that Russia was responsible for fake online content, a bold move, Kilicdaroglu said: "If we did not have it (concrete evidence), I wouldn't have tweeted." His party did not contact the Russian embassy over the issue, he added. He did not elaborate on what the online content was.
One presidential candidate from a small party, Muharrem Ince, withdrew on Thursday citing a faked "character assassination" carried out online. He gave few details.
Russia has been accused in the past of meddling in foreign elections including in the United States, which Moscow denies.
Turkey's vote on Sunday shapes up as the most consequential in its modern history, with huge implications for Ankara's global standing, strategic alliances and economic direction.
"We find it unacceptable for another country to interfere in Turkey's election process in favour of a political party. I wanted the whole world to be aware of this, that is why I made this call openly by a tweet," Kilicdaroglu said in an interview.
The Kremlin later denied interfering.
Kremlin spokesman Dmitry Peskov said the people who had passed on such allegations to Kilicdaroglu were liars and that Russia valued its ties with Turkey enormously.
In his office in Ankara, Kilicdaroglu reiterated his confidence that he would "replace an authoritarian rule".
The 74-year-old former civil servant stressed that Turkey, which also has close business, economic and tourist ties with Russia, would pursue a fine balance in relations with Moscow.
"We don't want to break our friendly relations but we will not allow interference in our internal matters," he said.
Kilicdaroglu also said he would push for another peace initiative between Russia and Ukraine, following a failed bid by Erdogan in 2022.
However, he added, "we should make it clear that we do not find it right for any country to occupy another country".
Turkey has conducted a diplomatic balancing act since Russia invaded Ukraine. Ankara opposes Western sanctions on Russia and has close ties with both Moscow and Kyiv, its Black Sea neighbours. It has sent armed drones to help Ukraine.
When asked whether he would support NATO enlargement if he is elected as president, he said: "Of course," without elaborating. "We will maintain our relations with NATO within the same framework as we had in the past," Kilicdaroglu added.
Finland and Sweden, rattled by Russia's invasion, secured approval to join NATO earlier this year, though Sweden's induction has been delayed by a dispute with Erdogan's government over its alleged harbouring of Kurdish militants, who Ankara considers terrorists.
Kilicdaroglu said a fundamental problem of Turkey's foreign policy in Erdogan's AK Party (AKP) tenure was the exclusion of the foreign ministry from the policy-making process. Erdogan has instead shaped policy himself.
Turkey, Kilicdaroglu said, will pursue a peace-oriented foreign policy that prioritises its national interest and acts in line with the modern world.
Kilicdaroglu said gains in Turkish assets on Thursday indicated markets believe his opposition alliance will win on Sunday. On Thursday, Turkey's main stock index closed almost 7.9% higher, while credit default swaps dropped.
The election pits Erdogan's vision of a heavily managed economy, which has seen soaring inflation and a plunging lira, against Kilicdaroglu's promise to return to a more orthodox, free-market economic policy.
"We already see that there is relief inside and outside the country as it has become clear that I will be elected as the president," Kilicdaroglu said, adding markets trusted that his alliance would rule with rational policies.
"This gives great confidence to domestic and foreign financial circles. [The market moves on Thursday] were the first steps of this trust. Turkey's borrowing costs will also decrease," Kilicdaroglu said.
"We need to appoint someone who is trusted by financial circles as the head of the central bank. This is the first thing foreign investors will see. Plus, we will ensure the independence of the central bank."
(Editing by Jonathan Spicer, Samia Nakhoul, Alexandra Hudson and Mark Heinrich)