ISTANBUL — President Recep Tayyip Erdogan of Turkey, holding a rare meeting with international journalists, said on Thursday that he expected to resolve disagreements with the United States, particularly his purchase of the Russian S-400 missile system, in a one-on-one meeting with President Trump at the end of the month.
The two leaders are expected to meet on the sidelines of the Group of 20 summit meeting in Osaka, Japan. Officials said they may also seek to finalize plans for Mr. Trump to visit Turkey in July.
Mr. Erdogan, who last gave an interview to an American newspaper in 2012, held the briefing with journalists just days before a rerun of a critical election for Istanbul mayor. The candidate for his Justice and Development Party, known as A.K.P., lost that race in March, and polls suggest he could lose again on Sunday.
But other than rejecting those polls, and insisting that he would accept the results even if the opposition wins again on Sunday, Mr. Erdogan seemed more interested in showing a statesmanlike manner before the G-20 meeting than in discussing the election.
Tensions between the United States and Turkey have gone up sharply over Turkey’s purchase of the S-400 missile system, Russia’s most advanced antiaircraft weaponry. The purchase would set off mandatory United States sanctions against Turkey, and it could create another slide in the value of the Turkish lira.
But Mr. Erdogan seemed confident on Thursday that his apparent rapport with Mr. Trump should be enough to ease the disagreement — and possibly avoid sanctions.
“They should think deeply, because losing a country like Turkey will not be easy,” Mr. Erdogan said of the United States. “If we are friends, if we are strategic partners, then we should handle this issue between each other.”
“I don’t think at all that the sanctions will happen,” he added.
Mr. Erdogan acquired sweeping new powers last summer when the country switched to a presidential system, and in recent years he has shown no hesitation to rule in an authoritarian style. He remains Turkey’s most popular politician by far, but recent polling in Istanbul has been one of several signs that the electorate is growing weary of the dominance of Mr. Erdogan and his party.
During the briefing, he emphatically endorsed his government’s candidate, Binali Yildirim, a former prime minister and close ally, in the mayor’s race. And he criticized the opposition candidate, Ekrem Imamoglu, without once naming him.
But he also said that he would accept the results this time even if the opposition wins again. Mr. Imamoglu spent 17 days as mayor before the election was overturned.
The loss of Istanbul would be a personal blow to Mr. Erdogan — he grew up in a working-class neighborhood on the Golden Horn, and the city has been both his home base and the center of his political power and prestige. It would also be a politically devastating loss, as much of his party’s financial resources come from supporters who have profited from municipal contracts in Istanbul, Turkey’s largest city and financial hub.