Kremlin spokesperson Dmitry Peskov warned of the possibility of escalation by Ukrainian forces around the separatist-held regions of eastern Ukraine.
Asked how likely such a development might be, Peskov said, "The level of danger remains high."
"We are drawing the attention of our interlocutors in every possible way to the dangerous concentration of forces (in Ukraine) and to the fact that a military operation and an attempt to resolve the issue by force in the southeast is quite likely," Peskov said in a conference call with reporters on Wednesday.
"This is real. We have all witnessed that Kyiv began a military operation in Donbas, started a civil war. There have been such precedents," he continued.
The US and its allies have warned of potential provocations or "false flag" attacks that might be orchestrated by Russia to potentially justify a military offensive against Ukraine.
The Donbas region has been under the control of Russian-backed separatists since 2014 and is referred to by Ukraine as "temporarily occupied territories." Russian forces are also present in the area, although the Kremlin denies it.
Peskov also used the call to welcome US President Biden's calls for diplomacy in a White House speech on Tuesday.