Greek lawmakers are due to vote Friday on a deal to change the name of neighbouring Macedonia and resolve a diplomatic dispute that has dragged on for nearly 30 years.
The vote was originally scheduled for after midnight Thursday but had to be postponed to Friday because some 230 lawmakers wanted to speak on the issue, the parliament speaker said.
Hundreds opposed to the deal protested outside parliament on Thursday evening, with police using tear gas to disperse them.
The vote on the agreement to rename Macedonia as the Republic of North Macedonia is now planned for around 2:30 pm (1230 GMT).
"Tomorrow is a crucial vote... now is the time to break free of the vicious cycle of nationalism and look at... future cooperation," Prime Minister Alexis Tsipras told the chamber.
Macedonia's parliament on January 11 backed a constitutional revision to change the country's name but for the deal to go through, it must also be approved by Greek MPs.
Communist party activists Thursday draped giant banners outside the Acropolis, the ancient citadel on an rocky outcrop overlooking Athens, reading: "No to the Tsipras-Zaev agreement."
That was a reference to the landmark compromise agreed in June between Tsipras and his Macedonian counterpart Zoran Zaev.
On Sunday, clashes between police and masked protesters left around 40 people injured as tens of thousands demonstrated in Athens against the name change.
According to the government, "the incidents were provoked by extremists, who attempted to enter parliament".
A wide range of Greek political parties, from Golden Dawn to the Socialists, oppose the accord.
But it could nonetheless be approved by the required 151 lawmakers in the 300-seat parliament.
The accord aims to start unravelling a diplomatic dispute that began nearly three decades ago with Macedonia's declaration of independence but whose roots date back centuries.
Since 1991, Athens has objected to its neighbour being called Macedonia because Greece has a northern province of the same name. In ancient times it was the cradle of Alexander the Great's empire, a source of intense pride for Greeks.
But the June agreement marks a landmark shift in the dispute, with the efforts of the two prime ministers winning them a nomination for the 2019 Nobel Peace Prize.