Ireland’s premier said coming to face to face with the horrors inflicted by Russia has convinced him that Ukraine will ultimately emerge from the war victorious.

Taoiseach Leo Varadkar pledged to stand with Ukraine for as long as it takes after holding talks with President Volodymyr Zelensky in Kyiv.

On a day-long unannounced trip to the Ukrainian capital, Mr Varadkar visited the sites of several atrocities committed in the early weeks of the Russian invasion.

He was taken to the church grounds where a mass grave was found and a bridge where fleeing civilians were bombed and laid a soft toy at a memorial for children killed in the conflict, the youngest just two days old.

The Taoiseach also participated in a number of other wreath and flower-laying ceremonies to commemorate those who have lost their lives defending Ukraine.

“I came face to face with the horror that Russia’s forces have inflicted on civilians here in Ukraine,” he said afterwards.

After an hour-long meeting with President Zelensky, Mr Varadkar reiterated Ireland’s support for Ukraine’s accession to the EU and called for the negotiation process to start before the end of the year.

He also committed to taking a lead role to set up international tribunals to prosecute crimes committed in Ukraine and to assist in efforts to de-mine vast swathes of Ukrainian land.

The Taoiseach made clear that while Ireland was militarily neutral it was not politically neutral, and announced an additional five million euro in humanitarian funding to help respond to the attack on the kakhovka dam and other areas.

“Perhaps Russia believes that it can break the resolve of the Ukrainian people, but I know from the way you fought for the past few years, and from my visit here, that it cannot,” he said.

“My visits to the sites of these atrocities this morning, and my meeting here in Kyiv, has confirmed to me that Russia will not succeed, and Russia cannot be allowed to succeed.

“This is the 21st century and the idea that national boundaries can be changed by violence, or the democratically elected governments can be overthrown by foreign invasion, must perish.

“We need to make sure that Ukraine succeeds, that it wins this war, so that no other country gets attacked.

“If Russia thinks that targeting civilians and essential infrastructure will discourage Ukraine’s friends, including Ireland, well, it’s wrong.”

He added: “We will stand with Ukraine for as long as it takes. Ukraine will prevail and Ukraine will be rebuilt.”

Mr Varadkar also revealed that an investigation is under way into an image of a drone downed in Ukraine which had a “Made In Ireland” stamp on it.

Asked how such a part could potentially have got into Russian hands, Mr Varadkar said: “We don’t believe any Irish companies have evaded sanctions, but there are third parties that find ways around the sanctions, and it’s really important that we crack down on that and we do take it very seriously.”

Mr Zelensky thanked the people of Ireland for taking in tens of thousands of Ukrainian refugees since the Russian invasion began.

“This is a significant moral support to our nation,” he said.

“You’ve hosted 86,000 Ukrainian citizens, you’ve provided them with accommodation, with funding, with access to education and health support, this is very important.”

Mr Zelensky said it was a “fruitful” meeting where they spoke about the sanctions package against Russia, about how to stop Russia producing missiles and Ukraine’s accession to the EU.

He also informed Mr Varadkar about the recent Russian attacks on its port cities, including Odesa. He said Russia was targeting residential areas and food infrastructure, which was not only an attack on Ukraine, but on “global stability”.

“It’s important that every country of the world which is striving for peace, for normal life, on all continents, it’s important for them to condemn the Russian terror and participate in common efforts to overcome this aggression,” he said.

“Ireland is participating in such common efforts.”

Mr Zelensky also said he was “very grateful” that the Taoiseach began his visit in Kyiv’s suburbs, stating that he had “seen with your own eyes the consequences of the war, the consequences of Russia’s aggression”.

After the engagement with the president, Mr Varadkar then met Ukraine’s Prime Minister Denys Shmyhal and the chairman of the Verkhovna Rada parliament, Ruslan Stefanchuk.

The Taoiseach’s intensive schedule of engagements began in the early morning when he disembarked from an overnight train from Poland to travel to the Kyiv Oblast region on the northern outskirts of the city.

He was taken to the small cities of Bucha and Irpin, where scores of civilians were killed during a period of Russian occupation at the start of the war.

In Bucha, Mr Varadkar visited the Church of St Andrew where a mass grave was discovered after Russian soldiers retreated from the area.

Inside the building he was shown an exhibition of images of the graphic scenes captured during the exhumation process.

Ukraine’s prosecutor general Andrei Kostin accompanied the Taoiseach on the visit and explained the work done to collect evidence for war crimes investigations and secure justice for those killed.

The Taoiseach’s tour also took him through the village of Horenka, where he was taken to an apartment block that was heavily damaged in a Russian aerial bombardment.

The shelling blew a huge hole in the side of the building and the interiors of the apartments that were destroyed are clearly visible.

Among the debris was a painting of an old man enjoying a bath, representing the defiance of residents.

Horenka is where Irish-born cameraman Pierre Zakrzewski was killed in a Russian attack in March 2022.

Mr Zakrzewski, 55, who worked for Fox News, was killed alongside Ukrainian freelance journalist Oleksandra “Sasha” Kuvshynova, 24.

The Irish premier also visited Moschun, a village that witnessed a pivotal battle in the fight to repel a full-scale invasion of Kyiv.

Mr Varadkar laid flowers and observed a moment’s silence to commemorate the Ukrainian fighters, most from the territorial reserves, who were killed in defence of the capital.

He also visited a bridge in Irpin where Russian forces bombed civilians fleeing the conflict. The bridge was later blown up by Ukrainian troops in an effort to prevent Russian tanks from entering Kyiv.

Later in the morning, Mr Varadkar visited Mikhailivska Square (St Michael’s Square) in central Kyiv, where he watched as two Ukrainian soldiers laid a wreath on behalf of the Irish Government at a ceremony at the Wall of Remembrance of the Fallen for Ukraine.

The Taoiseach was then shown the remnants of several Russian tanks and other military vehicles on display in the square.

Later in the day, Mr Varadkar met a Ukrainian actor who was assaulted in Dublin last month.

Oleksandr Hrekov was attacked in Dublin city centre shortly after performing at the city’s Abbey Theatre.

He was part of a Kyiv theatre company that had travelled to Dublin to put on a production of Translations by Irish playwright Brian Friel. The actor required stitches in hospital.

Mr Varadkar visited the Lesya Ukrainka National Academic Drama Theatre company in Kyiv on his visit to the Ukrainian capital.

They performed a song for the Taoiseach before presenting him with a copy of Translations signed by the cast.

The Taoiseach then spoke to Mr Hrekov, shaking his hand and enquiring about his well-being since the assault.