The inauguration in parliament will be followed by a lavish ceremony at his palace in Ankara attended by dozens of world leaders.

Turkey’s divisive leader won the May 28 runoff against a powerful opposition coalition, despite an economic crisis and anger over February earthquakes that killed more than 50,000 people.

Erdogan won 52.18 percent of the vote, while his secular rival Kemal Kilicdaroglu garnered 47.82 percent, official results show.

“As president, I swear on my honor and integrity, before the great Turkish nation … to work with all my power to protect the existence and independence of the state … and to fulfill my duty impartially,” Erdogan said in parliament after a ceremony outside the building where he saluted soldiers in pouring rain.

Supporters in parliament gave Erdogan a minute-long standing ovation after his swearing-in, while some opposition lawmakers refused to stand.

In his oath Erdogan also promised not to deviate from the rule of law and the secular principles of the republic founded by Mustafa Kemal Ataturk 100 years ago.

Turkey’s longest-serving leader now faces immediate challenges in his third term, including a slowing economy and tensions with the West.

“From a geopolitical point of view, the election will reinforce Turkey’s recent pursuit of an independent foreign policy,” said Matt Gertken, chief geopolitical strategist at BCA Research.

“This policy aims to extract maximum economic and strategic benefits from eastern and autocratic states while still preventing a permanent rupture in relations with Western democracies,” he said.

“Tensions with the West will likely increase again,” Gertken added.

Azerbaijan’s President Ilham Aliyev, Iran’s vice president Mohammad Mokhber, Kurdistan Region President Nechirvan Barzani, Hungary’s right-wing Prime Minister Viktor Orban and the speaker of the lower house of Russia’s parliament, Vyacheslav Volodin, were among the foreign guests expected at the ceremony.

Armenian Prime Minister Nikol Pashinyan will also be present, his office said, the latest sign of a thaw between the two arch-foes.