The White House says Ukraine will be at the top of President Barack Obama's agenda when he meets with Russian President Vladimir Putin in New York.
The Kremlin says the meeting is set for Monday when the United Nations General Assembly opens.
White House spokesman Josh Earnest said Obama wants to reinforce to Putin the importance of abiding by the Minsk agreement aimed at carrying out a cease-fire in Ukraine.
Earnest said separatist forces in eastern Ukraine who get important military support from Russia continue to destabilize Ukraine, while Western sanctions against Moscow weaken the Russian economy.
"So it is clear that Russia's international isolation and their continued refusal to abide by basic international norms, particularly when it comes to these combined Russian separatist forces, has taken a significant toll on their economy," he said.
A Kremlin spokesman said the issue of Syria will top the meeting and that both presidents will discuss Ukraine if there is time.
Russia has substantially bolstered its military presence in Syria, including sending in fighter planes and tanks.
Secretary of State John Kerry says U.S. military experts believe Russia is looking to protect its assets in Syria in the middle of an unstable war-torn country.
Russia has said it wants to destroy Islamic State and extremism, but its long-term plans for Syria are still unclear.
Earnest said the president will make it clear to Putin that boosting support for Syrian President Bashar al-Assad is a losing bet.
"The likely consequence of doing so is only to deepen and expand the ongoing crisis in that country. That doesn't serve the interests of either the Russian people or the American people," he said.
Earnest said one meeting is unlikely to give any insight on exactly what Russia's intentions are in Syria, but could lay the groundwork for what he calls "better coordination."
