US Secretary of State Antony Blinken spoke with French Foreign Minister Jean-Yves Le Drian about "concerning" Russian military activity taking place "in and near Ukraine," the US State Department said on Sunday.
The two top diplomats addressed "reports of concerning Russian military activity in and near Ukraine and their continued ironclad commitment to Ukraine's sovereignty and territorial integrity," the department's spokesman Ned Price said in a statement.
The US and the European Union have voiced increasing alarm over recent Russian troop movements near the country's border with Ukraine.
Ukrainian President Volodymyr Zelenskiy has said there are almost 100,000 Russian soldiers in the border region.
After discussing the issue of Russian military buildup near Ukraine with US President Joe Biden earlier this week, European Commission President Ursula von der Leyen said EU officials "fully support the territorial integrity of Ukraine."
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The Russian troop movements have spurred fears of a possible attack.
But Russia dismissed such suggestions as inflammatory.
Moscow instead complained about increasing NATO activity in the region and accused Washington of aggressive moves in the Black Sea, where Ukraine and the US held military drills on Saturday.
Ukraine has been engaged in a conflict with Kremlin-backed separatists in the Donetsk and Lugansk regions over the past seven years. It erupted after Russia annexed the Crimean peninsula in 2014.
Kiev said two Ukrainian soldiers were killed Friday by an explosive device in the country's separatist east. The conflict has so far claimed over 13,000 lives.
After an uptick in violence at the beginning of the year, Russia deployed around 100,000 troops on Ukraine's borders in the spring.
The move sparked fears of a major escalation in the conflict.
Russia later announced a pullback but both Ukraine and the US said at the time that the withdrawal was limited.
Ukraine and its Western allies accuse Russia of sending troops and arms across the border. Moscow has denied those claims.
They also blame Russia for the migrant crisis on the EU's eastern border involving Belarus.
Western countries have accused Belarusian President Alexander Lukashenko's government of causing the crisis by encouraging migrants from the Middle East to come to Belarus and then taking them to the border.
Lukashenko, who has been in power for nearly 30 years and has led a bloody crackdown against his opponents, denies the charges, pointing the finger of blame in the West's direction.
Russian President Vladimir Putin has also rejected the accusations of being involved in the crisis.
On Sunday, the US said Belarus' actions "threaten security, sow division, and aim to distract from Russia's activities on the border with Ukraine."
And French President Emmanuel Macron said Friday that he will speak with Putin in the "coming days" about the situation in Ukraine and Belarus.