The White House praised Turkey's government for apologizing for the use of force against protestors in the biggest mass demonstrations of Prime Minister Recep Tayyip Erdogan's decade in power.
Deputy Turkish Prime Minister Bulent Arinc said earlier the government had "learnt its lesson" and regretted using security forces against people with "rightful demands."
"We welcome the deputy prime minister's comments apologizing for excessive force, and we continue to welcome calls for these events to be investigated," White House spokesman Jay Carney said.
"We hope that, as we have made clear, that the Turkish government will handle this in a way that respects the rights of free speech and assembly."
Erdogan, who was in Washington just last month, is a key regional ally for the United States as it struggles to respond to the civil war in Syria and seeks to cope with fast-changing political dynamics in the Middle East.
Vice President Joe Biden also weighed in, in a speech to the US-Turkish Council's annual conference in Washington.
"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, speaking up for the right of free assembly and an unfettered media.
"The United States stands for certain clear principles in these circumstances," Biden said, while praising Turkey as a "vital ally" and an emerging major power crucial to US foreign policy interests.
Arinc said clashes had left about 300 people wounded in five days though rights groups and doctors have put the number of injured in the thousands and said two people have been killed.
He called on "responsible citizens" to stop the protests, but hundreds of demonstrators defied his message and returned peacefully within hours to Taksim Square, the cradle of the protests in Istanbul.
They repeated their charges that Erdogan was imposing conservative Islamic reforms on the predominantly Muslim but constitutionally secular nation.
Arinc made his comments after meeting with President Abdullah Gul, and US State Department spokeswoman Jen Psaki also praised "the efforts by president Gul and others to calm the situation."
"We're hopeful that that will have an impact on the country and think that's a positive step," she told reporters.
US Secretary of State John Kerry had earlier voiced concern over the excessive use of force by Turkish police to quell the demonstrations, and backed the right of all people to demonstrate peacefully.
