Ukraine's security council on Wednesday approved plans to declare a state of national emergency, in response to the growing regional tensions.
The measure, which must be formally approved by parliament, requires stepped-up document and vehicle checks, among other measures, the council's secretary Oleksiy Danilov said.
Danilov said he would deliver a report to Ukraine's parliament later on Wednesday, with lawmakers expected to approve the added security measures this week.
They would apply to all parts of Ukraine except for its two Russian-backed eastern regions.
Danilov said each of Ukraine's regions would be able to select which particular measures to apply, "depending on how necessary they might be".