Boris Johnson told Vladimir Putin that an invasion of Ukraine would be a “tragic miscalculation”, Downing Street said following a call between the two leaders, writes POLITICO.

In a readout Wednesday evening, a spokesperson for the U.K. prime minister’s office said Johnson “expressed his deep concern about Russia’s current hostile activity on the Ukrainian border”. Moscow has amassed 100,000 troops at the border in recent weeks amid mounting Western concern it is preparing an invasion.

And, the spokesperson said, Johnson stressed that “any further Russian incursion into Ukrainian territory would be a tragic miscalculation”.

Downing Street claimed that the pair also agreed that it was “in no one’s interest” to allow the situation at the Russian-Ukrainian border to deteriorate any further.

Johnson restated his view that Ukraine is entitled to join NATO if it wants because it is a sovereign state, and underscored the need to find a diplomatic solution to the crisis, including by involving Kyiv.

According to the Kremlin’s own readout of the conversation, Putin criticized Ukraine’s “chronic sabotage of the Minsk agreements” - meant to end war in the Donbas region of Ukraine - and “NATO’s unwillingness to adequately respond to well-founded Russian concerns.”