(Adds Kremlin quote)
MOSCOW, April 18 (Reuters) - The Kremlin on Friday described as unacceptable a U.S. threat to impose sanctions if Russia fails to fulfil its side of an international deal on Ukraine, accusing the White House of treating Moscow like a "guilty schoolboy".
President Barack Obama said Thursday's deal in Geneva between Russia, Ukraine and Western powers to reduce tensions in the Russian-speaking east of Ukraine was promising but that Washington and its allies were prepared to impose more sanctions on Russia if the situation fails to improve.
"Statements like those made at a high level in Washington that the United States will follow in detail how Russia fulfils its obligations ... are unlikely to help dialogue," President Vladimir Putin's spokesman, Dmitry Peskov, said.
"You can't treat Russia like a guilty schoolboy who has to put a cross on a piece of paper to show he has done his homework," Peskov said in an interview with Russia's First Channel. "That kind of language is unacceptable."
Thursday's deal called among other things for all illegal armed groups to disarm and end occupations of public buildings in Ukraine's east that Ukrainian authorities say have been orchestrated by Russia's intelligence services.
But pro-Russian separatists, over whom Moscow says it has no control, dismissed the accord, saying they were not bound by it.
Russia's Foreign Ministry accused U.S. officials of seeking to whitewash what it said was the use of force by the Ukrainian government against protesters in the country's mainly Russian-speaking eastern provinces.
"The blame for the Ukrainian crisis and its current aggravation is unreasonably being placed on Russia," the ministry said in a statement.
"The American side is once again stubbornly trying to whitewash the current actions of Kiev's authorities, who have embarked on a course for the violent suppression of protesters in the southeast who are expressing their legitimate indignation over the infringements of their rights." (Reporting by Alissa de Carbonnel and Conor Humphries; Editing by Mark Heinrich)