The United States on Tuesday marked the third anniversary of a deal that ought to have ended the war in Ukraine by demanding Russia end its "aggression" and give up Crimea.
And the State Department warned that US sanctions imposed on Russia to punish its intervention in its neighbor will remain in place until Ukraine's sovereignty is restored.
In a statement, spokeswoman Heather Nauert accused Moscow of "stoking a hot conflict in Ukraine that has cost over 10,000 lives, including more than 2,500 civilians."
Three years ago on Monday, Russia and Ukraine signed a "Package of Measures for the Implementation of the Minsk Agreements."
Under the Minsk agreement -- brokered by France and Germany -- Ukraine agreed to carry out political reforms while Russia agreed to end its support for pro-Russian separatist rebels.
But fighting has continued, and Washington accuses Moscow's forces and proxies of intimidating unarmed monitors from the Organization for Security and Cooperation in Europe (OSCE).
"Working closely with France and Germany, the United States continues to urge the Russian government to cease its aggression in Ukraine," Nauert said.
"The United States takes this opportunity to reiterate that our sanctions will remain in place until Russia fully implements its commitments under the Minsk agreements."
The separate Crimea-related sanctions "will remain in place until Russia returns the peninsula to Ukraine," Nauert said.
In addition to allegedly backing rebels in the Ukrainian regions of Lugansk and Donetsk, Russian regular forces seized Crimea in February 2014 and Moscow has formally annexed it.
This has not been recognized by the bulk of the international community.
Next month, President Vladimir Putin will stand of re-election on the fourth anniversary of the Crimean annexation, symbolically underlining its importance to the Kremlin.