US Secretary of State John Kerry was speaking after Turkey's labour minister suggested the US was behind the coup.
Turkish President Recep Tayyip Erdogan has called on the US to extradite US-based Turkish cleric Fethullah Gulen.
Mr Erdogan has accused him of being behind the plot, which Mr Gulen denies.
Mr Gulen told reporters from his home in Pennsylvania that he had been away from Turkey for more than 15 years and "I don't even know who my followers [in the country] are".
The attempted coup began on Friday night when a faction of the military took over key bridges in Istanbul and attacked parliament buildings in Ankara.
The government says 161 civilians and 104 "plotters" were killed in ensuing clashes, and more than 1,440 injured.
Nearly 3,000 soldiers have been detained and some 2,700 judges were sacked on Saturday as the government sought to re-assert its power.