Ukrainian President Volodymyr Zelenskiy said after a visit to a western region to discuss border defenses on January 11 that Ukrainian forces "must be ready both at the border and in the regions."
The comments come amid speculation about the potential for a renewed Russian offensive via neighboring Belarus.
Senior Ukrainian military and political officials have recently warned of a possible repeat of the ultimately unsuccessful invasion at the start of the war in February from the north targeting Kyiv, although a fresh U.K. intelligence assessment played down the significance of newly deployed aircraft and planned Russian-Belarusian military exercises later this month.
Zelenskiy said after the stopover in Lviv that he spoke with officials about "state border protection, the operational situation on the border with the Republic of Belarus, and counter-subversive measures in these territories."
"We understand that apart from powerful statements, we do not see anything powerful there, but nevertheless we must be ready both at the border and in the regions," he said, according to Reuters.
The British Defense Ministry's daily intelligence assessment on January 11 noted the announcement of a joint Russian-Belarusian tactical flight exercise in the second half of January and downplayed additional Russian military helicopters' new presence near Minsk.
Addressing persistent fears of a spread of the 10-month-old full-scale conflict, the British ministry tweeted on January 11 that a new deployment of Russian aircraft to Ukraine's northern neighbor Belarus "is likely a genuine exercise, rather than a preparation for any additional offensive operations against Ukraine."
It noted the arrival by amateur spotters of military helicopters at Machulishchy air base near the Belarusian capital, "some appearing with 'Z' markings" that have been used by Russian forces in the invasion of Ukraine.
But it said Russian aircraft in Belarus "are mostly involved in training" and the new helicopters were "unlikely to constitute a credible offensive force."
Russia's invasion was partly staged in Moscow-allied Belarus, although leader Alyaksandr Lukashenka has sought to downplay his regime's role in the conflict.
The commander of Kyiv's defenses, Lieutenant General Oleksiy Pavlyuk, said on January 10 that Ukraine's military had strengthened its defensive positions north of the city and was girding for a potential offensive from across the nearby Belarusian border, according to dpa.