Vice President Joe Biden urged Turkey's government on Tuesday to respect the rights of its political opponents after a violent crackdown against anti-government protesters raised concerns about the NATO ally.

Turkey's deputy prime minister, Bulent Arinc, issued an apology to people involved in a protest last week when a group demonstrating against plans to build at an Istanbul park was met with teargas and water cannons.

That protest then grew into the biggest and most violent anti-government demonstration in years as Turks complaining of what they say is Prime Minister Tayyip Erdogan's authoritarian style took to the streets in dozens of cities.

Biden, speaking to the American-Turkish Council, said Turkey stood a chance to reach its goal of becoming one of the world's 10 largest economies by 2023, but that it should not stray from democracy.

"Turkey's future belongs to the people of Turkey and no one else. But the United States does not pretend to be indifferent to the outcome," Biden said.

Countries with open societies, political systems and economies, democratic institutions and a firm commitment to universal human rights are the countries that will thrive and be the most powerful countries of the 21st century, he said.

"Today's Turkey has a chance to demonstrate that there's no need to choose between economic advancement and democracy, the system that empowers the winners of elections and yet protects those who are in the opposition," said Biden.

Secretary of State John Kerry, who said on Monday he was concerned by reports of excessive police force, spoke with Turkish Foreign Minister Ahmet Davutoglu en route to an Organization of American States meeting in Guatemala, a State Department official said on Tuesday.

"The foreign minister provided the secretary the government of Turkey's perspective on the recent protests in Turkish cities. The secretary welcomed the update on efforts to calm the situation," the official said.

White House spokesman Jay Carney noted Arinc's comments.

"We hope that ... the Turkish government will handle this in a way that respects the rights of free speech and assembly that are elemental to democracies. And we welcome the deputy prime minister's comments apologizing for excessive force and we continue to welcome calls for these events to be investigated," Carney told a briefing.

Arinc's comments contrasted with remarks by Erdogan, who said on Monday that protesters were "arm-in-arm with terrorism."