American officials had contacted Russia shortly before Joe Biden's departure from Washington to avoid any miscalculation that could bring the two nuclear-armed nations into direct conflict.

As AP reports, Biden's visit marked the rare occasion when a U.S. president has traveled to a conflict zone where the U.S. or its allies did not have control over the airspace.

According to the publication, the White House said that shortly before Biden's departure from Washington "for deconfliction purposes" in an effort to avoid any miscalculation that could bring the two nuclear-armed nations into direct conflict.

While Biden was in Ukraine, U.S. surveillance planes, including E-3 Sentry airborne radar and an electronic RC-135W Rivet Joint aircraft, were keeping watch over Kyiv from Polish airspace.

It was rumoured about U.S. President's announced visit to Kyiv where were applied large-scale traffic restrictions on the morning of February 20. Around noon, Volodymyr Zelenskyy and the White House confirmed that Biden was indeed in Kyiv.

According to the American media, Joe Biden traveled to Kyiv from the border with Poland by train, and the White House kept his visit a complete secret until the end.

As reported, US President Joe Biden, during his visit to Kyiv, announced a new package of US military assistance and additional sanctions against Russia for its aggression.