U.S. President Barack Obama has challenged Russia to back peace rather than war in Syria and said a negotiated truce that is supposed to begin this week will be a "test" of Moscow's intentions.
Obama challenged recent assertions by Russian and Syrian leaders that they are winning the ground war against rebel groups in the "shattered" country.
Syrian President Bashar al-Assad's troops, backed by Russian air strikes, may have made "initial advances," but three-quarters of the country remains out of their control, Obama told reporters in California after an East Asian summit on February 16.
The president said Russia's and Syria's gains, moreover, have come at a horrible cost in human lives and displacement of thousands of Syrians, much of that the result of Russia's "indiscriminate" bombing.
"The real question in Syria is what is it that Russia thinks it gains if it gets a country that has been completely destroyed as an ally and that it now has to...spend billions of dollars to prop up," he said.
"A country has been shattered because [Assad] was willing to shatter it," he added, and Russia "has been party to that entire process."
What forced Russia to intervene in Syria was the Syrian regime's weakness, not its strength, Obama said.
"You send in your army when the horse you're backing isn't effective," he said, asserting that Russia's deep recession and faltering government revenues will not permit Moscow to support a long war there.
"Putin may think he's prepared to invest in a permanent occupation of Syria," Obama said, but "that's going to be pretty costly...If you look at the state of Russia's economy, that's not what would be best for Russia."
Obama said it would be smarter for Putin to help broker a peace settlement and political transition in Syria, and this week's truce gives him the opportunity to get started on that process.
The president's comments were echoed by other administration officials earlier on February 16.
State Department Spokesman Mark Toner said the United States expects Russia to honor the truce, which negotiators in Munich last week said should begin by February 19, and wants to "see some progress on a cessation of hostilities."
Pentagon press secretary Peter Cook said the truce agreement is a "test" and "a new marker" for Russia.
"We will be keeping a close eye on who abides by it and who does not, and we will be in a position to say clearly, and to respond if necessary, if there are violations of that cessation of hostilities," Cook said.
