The American Secretary of State John Kerry says there is no new deal on Ukraine, despite four hours of "frank" talks with Sergei Lavrov.
Mr Kerry was speaking at a news conference after holding crisis talks with the Russian foreign minister in Paris. He said the US still considered Russian actions in Crimea to be "illegal and illegitimate".
Earlier, Mr Lavrov set out demands for a neutral and federal Ukraine.
Mr Kerry said the federalisation of Ukraine was up to Ukrainians. He said he had also raised "strong concerns" about the presence of Russian troops on the Ukraine border, which he said created a climate of fear and intimidation.
However, Mr Lavrov has categorically denied any plans for an invasion.
Mr Lavrov told Russian state TV before the talks that Ukraine should come up with a new constitution "providing for a federal structure" and neutrality.
The Ukrainian foreign ministry said it deeply regretted Mr Lavrov's "patronising" remarks.
"The US and Russia have differences of opinion on the events that led to this crisis - but both of us recognise the importance of finding a diplomatic solution," Mr Kerry told the news conference late on Saturday.
Russian Foreign Minister Sergei Lavrov: "We have absolutely no intention of, or interest in, crossing Ukraine's borders"
He said both countries had agreed to work with the Ukrainian government to assure priorities such as the rights of national minorities, disarmament of irregular forces and provocateurs, and constitutional reform.
Moscow claims that "fascists" have taken power in Ukraine, jeopardising the safety of Russian speakers.
As the rest of Europe put clocks forward by one hour on Sunday, Crimea aligned its time with Moscow, jumping two hours ahead. Hundreds of people waving flags greeted the time change in the capital, Simferopol.
Voters in the mainly pro-Russian peninsula backed leaving Ukraine for Russia in a referendum a fortnight ago. But the vote has been condemned as illegal by Kiev and the UN General Assembly.
Russia has taken over most of Ukraine's military bases in Crimea.
The Pentagon believes Moscow has massed tens of thousands of troops close to Ukraine's eastern border, prompting fears of an invasion.