Turkish President Recep Tayyip Erdogan, who has been reportedly unwell since Tuesday evening, appeared in public for the first time on Saturday in Istanbul. The Turkish leader was visiting the Teknofest air show at Istanbul's old Atatürk airport, an event that showcases the military's drones and aircraft. Erdogan is seeking a third presidential term in Turkey's May 14 elections. The head of state is due to take part in an election rally in Izmir, on the west coast, later Saturday. He is also expected in the capital Ankara on Sunday, exactly two weeks before the first round of voting, to resume his election campaign after a four-day break this week. Erdogan also spoke by phone Friday with UN Secretary-General Antonio on several matters, including the Ukraine-Russia grain and fertilizer deal they helped arrange, UN spokesman Stephane Dujarric said. He said they discussed "how to guarantee the improvement, expansion and extension" of the deal, which expires May 18. Erdogan became ill during a TV interview on Tuesday evening with what Health Minister Fahrettin Koca later said was a "gastrointestinal infection". His election rallies planned for Wednesday and Thursday were canceled. Smiling and dressed in a red windbreaker, the 69-year-old leader walked out on the stage of an Istanbul aviation festival and tossed out flowers to flag-waving supporters. He arrived to the event on Saturday with his close ally, Azerbaijani President Ilham Aliyev, and Libyan Prime Minister Abdul Hamid Dbeibah. Both countries have fought wars using Turkey's combat drones, which will feature prominently at the weekend aviation event. Erdogan had been laying low since getting sick live on television on Tuesday night. Erdogan is reportedly to have suffered from gastroenteritis. The digestive problem is easily treated and usually clears up in a few days. However, it has disrupted Erdogan's attempts to seize momentum in the run-up to Turkey's most important election in generations in approximately two weeks. Erdogan looked healthy addressing the crowd with a microphone in his hand, describing government efforts to help the victims of a massive February earthquake that claimed more than 50,000 lives. But he refrained from addressing his absence or the health scare. Erdogan's illness came at one of the more vulnerable moments of his two-decade rule. Most polls show Erdogan slightly behind the main opposition alliance's candidate Kemal Kilicdaroglu. His conservative party's control of parliament through an alliance with ultra-nationalist group Nationalist Movement Party is also under threat. Kilicdaroglu has formed the type of broad-based coalition that Erdogan had mastered in crafting over 20 years. The opposition alliance includes some of Erdogan's former allies, liberals, conservatives and nationalists. Turkey's pro-Kurdish party also announced backing for Kilicdaroglu although it is not officially in the opposition alliance. — Agencies