Russia has legitimate fears over the risk of American military hardware being stationed close to its borders, the country’s president, Vladimir Putin, has said, insisting he still hopes talks with Washington can ease tensions.

Speaking alongside Greek Prime Minister Kyriakos Mitsotakis at a press conference in Sochi on Wednesday, Putin said that “it would be criminal inaction on our side to spinelessly watch all that’s taking place” when it comes to the prospect of neighboring Ukraine joining NATO.

According to him, “Russia conducts peace-loving foreign policy, but we have a right to provide for our own safety,” cautioning that the US-led military bloc’s weapons could be deployed further and further eastwards if Kiev’s long-standing hopes for membership were granted.

However, Putin added, negotiations held the day before with American President Joe Biden could still help to de-escalate tensions that have flared between Moscow and Washington in recent weeks. “The talks were very open, substantive, and constructive. I hope that the American side sees the results the same way. We have the possibility of continuing the dialogue, that’s the most important thing,” the Russian leader added.

Asked about the possibility of Moscow launching an invasion against Ukraine, Putin said the question was “provocative,” insisting that his country would act only in self-defense.

“We are, of course, concerned about the potential membership of Ukraine in NATO, because that would result in military bases and troops being placed in the territory of Ukraine,” he added.

Officials in Kiev and Washington have issued a series of warnings in recent weeks, claiming that Russia could launch an all-out offensive against its neighbour.

The Kremlin has consistently rejected the claims, with Putin’s press secretary, Dmitry Peskov, blasting the purported invasion plans as “baseless,” insisting the rhetoric is part of a US-led “disinformation” campaign. The top official also mocked satellite imagery used to evidence the reports in Western media, pointing out the photographs showed military hardware hundreds of miles from the Ukrainian border, closer to Belarus.

Biden and Putin held talks on Tuesday via a secure video link, with Moscow describing the discussions as “frank and businesslike.” According to the White House, Biden “voiced the deep concerns of the US and our European Allies about Russia’s escalation of forces surrounding Ukraine and made it clear that the US and our Allies would respond with strong economic and other measures in the event of military escalation.”

According to a statement from Russian officials, Putin responded that it was NATO “making dangerous attempts to conquer Ukrainian territory” and “building up its military potential at our borders.” Ahead of the meeting, the Russian president said he would seek written guarantees that the bloc would not attempt to expand further eastwards.