The first official visit by a Turkish president to Greece in six decades got off to a tense start Thursday, with Recep Tayyip Erdogan repeating comments that have alarmed his Greek hosts about the need to “update” the 1923 treaty that delineated the borders of modern Turkey, AP reported.

Erdogan’s first meeting was with Greek President Prokopis Pavlopoulos, and the televised discussions between the two men were visibly awkward.

“In fact, all agreements in the world should be updated with the passage of time,” Erdogan said. “This update would be beneficial not only for Turkey but also for Greece.”

His comment “raises serious concerns and questions,” said government spokesman Dimitris Tzanakopoulos. “The Greek government and the prime minister want his visit to be a reason to build bridges, not to raise walls.”

Respecting the treaty is “the exclusive and non-negotiable foundation on which the honest cooperation of the two countries can be built,” Tzanakopoulos said.

But Erdogan reiterated his views on the treaty during his meeting Thursday with Pavlopoulos.

“This happened in Lausanne, that happened in Lausanne. I get that, but let’s now quickly do what is necessary,” he told the Greek president.

“Many things have changed in 94 years. If we review these, I believe that all the sides will agree that so many things have to (change.)”

Pavlopoulos told Erdogan the treaty “doesn’t need revision or updating. It is valid as is.” He added the treaty didn’t allow space for territorial disputes and clearly set out the status for Greece’s Muslim minority.

“It is clear that to achieve our goals and to make this visit a historic one ... this requires the full respect of international law,” Pavlopoulos said.

Erdogan’s televised chat with Prime Minister Alexis Tsipras immediately afterward was calmer.

“We have to put the ‘empty’ side of the glass to one side and focus on its full side. We have to build our negotiations on this,” Erdogan told Tsipras. “We have no designs on neighboring countries’ territories. But in the past, we were nations that lived one within the other.”

He noted that “mistakes” had led to the dwindling of Turkey’s Greek community, which largely fled the country after decades of persecution, leaving a very small minority still in Istanbul.

“We are leaving such mistakes to history. We have to build the future on stronger ground... If we manage to form a shared wisdom we can resolve (issues),” he said.

Tsipras, for his part, noted that Greece and Turkey had long had differences.

“What matters is that beyond those differences, we look for common ground and that the differences are addressed in a constructive way, with respect to the other’s opinion and without provocations and exaggeration,” he said.