"We are concerned about the number of people who were injured when police dispersed protesters in Istanbul's Gezi Park," said State Department spokeswoman Jennifer Psaki.
"We believe that Turkey's long-term stability, security and prosperity is best guaranteed by upholding the fundamental freedoms of expression, assembly and association, which is what it seems these individuals were doing.
"These freedoms are crucial to any healthy democracy," Psaki added yesterday.
Riot police in Istanbul used tear gas and water cannons earlier to break up the protest, which spiraled into a wider outcry against Prime Minister Recep Tayyip Erdogan's increasingly authoritarian government.