Kyiv, Ukraine - A trip abroad by a US president usually involves such strict security measures that whole cities come to a standstill when the high-profile leader finally arrives. But Joe Biden's surprise visit to Kyiv on Monday was always going to be different in many ways.

For starters, the trip was the first one by an American president to a war zone without US military being on the ground, which made it even more challenging from a security perspective, according to the White House.

The trip, ahead of a scheduled visit to Poland later on Monday, was long kept secret for security reasons. The White House had repeatedly denied rumors that Biden would take the opportunity to visit neighboring Ukraine.

Russia had been informed shortly ahead of the trip, however, according to US National Security Advisor Jake Sullivan.

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When it came to the actual travel arrangements, adjustments also had to be made.

The US president is usually accompanied by a large retinue, including a throng of journalists and security personnel. Biden also usually travels in his own armored limousine, dubbed the Beast.

But on his trip from Washington to Kyiv, via Germany and Poland, only two reporters travelled with the US president, and according to them, it was a presidential visit quite out of the ordinary.

Biden left the Andrews US Air Force base near Washington early on Sunday morning, but instead of the Air Force One he boarded a much smaller, and therefore much less conspicuous, plane.

En route to Poland, the plane touched down at the US Air Force base in Ramstein in western Germany to refuel, the two journalists reported following the conclusion of the highly symbolic visit on Monday evening.

From there, the plane travelled on to the Polish town of Rzeszów, near the Polish-Ukrainian border, where a convoy of SUVs, vans and other vehicles awaited to bring Biden to the railway station in Przemyśl, a small town some 55 miles away.

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In Przemyśl, the vehicle with the US president on board approached the waiting train as closely as possible to allow Biden to board as quickly as possible – and probably without giving anyone the chance to recognize him.

According to the two journalists travelling with him, the train was made up of some eight cars, many of which were occupied by security personnel.

The train crossed the Ukrainian border at around 10 PM and arrived in Kiev at 8 AM the next day, following a 10-hour train ride through war-torn Ukraine.

From the railway station, it was another ride in a convoy of armored vehicles to the presidential palace, where Biden met with Ukrainian President Volodymyr Zelensky.

The memorable visit was also a brief one, with Biden and his retinue back on the train to Poland some five hours later.