PRAGUE/KYIV: When headlines flashed on Tuesday morning that the leaders of Poland, the Czech Republic and Slovenia were on a train to Kyiv for talks with the Ukrainian president, it was news to some members of their immediate families.

The trip to a city under siege, where Ukraine's military is fighting invading Russian forces just a few kilometres from the periphery, was hastily arranged and known only to a few people.

Public pronouncements by the leaders and by a participant and a diplomatic source who spoke privately point to an arduous and risky diplomatic mission that underlined the sense of urgency among European countries to end the war.

While other European leaders were informed of the proposed journey during a summit in Versailles last Friday, only a small number of countries were directly involved.

The three that eventually took part are deeply suspicious of how Moscow views nations once under its influence before the collapse of the Soviet Union in 1991, concerns that have been heightened by its invasion of Ukraine that began on Feb. 24.

More than 3 million people have also fled Ukraine in the last three weeks, nearly 2 million of them into neighbouring Poland.

Asked about the danger involved, Czech Prime Minister Petr Fiala told reporters on Wednesday after his return from Ukraine that he believed it was worth the risk.

"There are situations where you have to decide for yourself, and I made the decision I made," the 57-year-old said.

"I was not alone, I had colleagues - the prime ministers, I had colleagues from my team and from the security service who were willing to complete the trip with me."

He told his wife about his plans, but asked her not to tell his mother or three children.

"They found out about it when it was published."

With him in Kyiv were Polish Prime Minister Mateusz Morawiecki, Slovenian counterpart Janez Jansa and Jaroslaw Kaczynski, powerful leader of Poland's ruling party.

They travelled on a special train from Poland's eastern border into Ukraine on Tuesday morning. By the time the trip became public, they were on their way to the capital.

A social media post on Wednesday showed Fiala in a flak jacket and helmet, looking at a mobile phone and standing between two beds in a narrow, rudimentary sleeping compartment.

It was not clear whether Russia knew of the visit.

Fiala posted on his Facebook page that the international community was informed of it via international bodies like the United Nations.

Polish Deputy Foreign Minister Pawel Jablonski said the participants did not discuss it directly with Moscow in advance.

"We would like to have somebody credible to discuss things with in Russia but Russia is no longer a reasonable partner for any discussions," he said on Wednesday.

The Kremlin did not immediately respond to a request for comment on whether it had been made aware of Tuesday's mission and had agreed to provide safe passage.


LONG WAIT, NO LIGHTS

A European diplomatic source said the plan was first mentioned to Charles Michel, European Council president, on the sidelines of the Versailles summit.

Morawiecki then let Michel and European Commission President Ursula von der Leyen know on Monday that they intended to travel the following day, according to a EU official. There was no European mandate.

It is not clear who else was approached to join them. French President Emmanuel Macron was not asked, according to the diplomat, and nor was German Chancellor Olaf Scholz, a spokesman said.

Slovakian Prime Minister Eduard Heger consulted his security services about it, a government spokeswoman said, but was strongly advised not to go.

On the morning the four politicians and their small entourage of advisers and security personnel crossed into Ukraine, at least five people had been killed in air strikes and shelling of Kyiv as Russia's assault intensified.

The city's mayor, Vitali Klitschko, declared a 35-hour curfew from Tuesday evening, saying that the capital was facing a "dangerous moment".

Thousands of people have been killed in the conflict. Russia calls its actions a "special operation" to demilitarise and "denazify" Ukraine, a charge Kyiv rejects as a false pretext to invade.

One participant in the mission, who declined to be identified due to the sensitivity of the visit, said the train journey took some 10 hours and that darkness had fallen by the time they reached Kyiv.

The delegation was taken in vans through largely empty streets to the presidential palace, where they waited for around four hours to see President Volodymyr Zelenskiy. They were not allowed their mobile phones during this period.

After the meeting, which lasted about 2.5 hours, they addressed a small group of reporters before departing back for Europe, and the participant said they probably got around three hours' sleep during the whole journey.

According to a Reuters witness, at the palace sandbags were piled up at various points and heavily armed Ukrainian security personnel escorted the delegation with flashlights along darkened corridors to avoid making the building a target.

Dressed casually, the leaders gave a press conference in which they expressed support for Ukraine's push to join the European Union and admiration for the country's resilience.

"The main message of our mission is to say you are not alone. Europe stands with your country," Fiala said.


DAMNED IF YOU DO...

While the mission had many admirers, some EU sources said it raised eyebrows among some member states who worried that a major incident involving the delegation could have dragged them closer into direct confrontation with Russia.

Polish state media, which broadly supports Kaczynski's PiS party, and Morawiecki himself have drawn parallels between the Kyiv mission and a trip made by Kaczynski's late twin brother Lech to Georgia in 2008 during tensions with Russia.

Lech Kaczynski, then Poland's president, came under fire near a breakaway Georgian province backed by Moscow, and lashed out against what he called Russian "imperialism".

"There's always another step. If you allow imperialists, there are always more countries in line," the president's aide told Polish television at the time.

Lech Kaczynski died when his plane crashed in thick fog over western Russia in 2010.

Radek Sikorski, a European parliamentarian for the main Polish opposition party Civic Platform, criticised Jaroslaw Kaczynski's participation in the Ukraine mission, saying on Twitter that it smacked of a PR stunt.

Slovakian premier Heger's defence minister, Jaroslav Nad, took to Facebook to defend his leader's decision not to join the trip, after a media backlash.

"I stand behind ... Heger and say repeatedly that this was the right decision," he wrote.

It is unclear whether the mission will have a significant impact on the war. Kaczynski proposed sending an international peacekeeping mission to Ukraine, but the idea does not appear to have gained immediate traction in talks between Kyiv and Moscow.

The symbolism of the trip, however, was not lost on Zelenskiy, who has vowed to repel the Russians and urged the West to impose a no-fly zone over Ukraine.

Noting that many ambassadors had left Kyiv, he said the visiting leaders were "not afraid of anything."

READ MORE: Latest development on Ukraine-Russia crisis