Washington - President Barack Obama and Russian President Vladimir Putin spoke for the first time in more than two weeks but showed little sign of agreement Monday, with the US leader urging pro-Russian forces to de-escalate the situation in eastern Ukraine and Putin denying that Moscow was interfering in the region.
Putin told Obama reports of Russian interference in the region were "based on unreliable information." The Russian leader also urged Obama to discourage the Ukrainian government from using force against those protesters.
The White House said Russia initiated the phone call, which came as pro-Russian forces deepened their insurgency in Ukraine's east, seizing more than a dozen government buildings.
"The president expressed grave concern about Russian government support for the actions of armed, pro-Russian separatists who threaten to undermine and destabilise the government of Ukraine," the White House said in a description of Obama's call with Putin.
"The president emphasized that all irregular forces in the country need to lay down their arms, and he urged President Putin to use his influence with these armed, pro-Russian groups to convince them to depart the buildings they have seized."
Both sides did suggest that plans would go forward for talks on Thursday in Geneva between the US, Russia, Ukraine and Europe.
But the White House said Obama told Putin that while a diplomatic solution remained his preferred option, "it cannot succeed in an environment of Russian military intimidation on Ukraine's borders, armed provocation within Ukraine, and escalatory rhetoric by Kremlin officials".
Obama and Putin last spoke on 28 March. Since then, pro-Russian forces have occupied local government offices, police stations and a small airport in eastern Ukraine.
The Ukrainian government has proved powerless to rein in the separatists, who are demanding more autonomy from the central government in Kiev and closer ties to Russia.
The White House has blamed the unrest on Russia, saying there are undeniable similarities between the situation in eastern Ukraine and the Kremlin's manoeuvres in Crimea, the Black Sea peninsula Russia annexed from Ukraine last month.