The European Union pledged Monday long-term support for Ukraine as the bloc's top diplomats met in Kyiv for a historic first gathering outside the bloc's borders.

The meeting came as disagreements grow among EU members over support for Ukraine and as Kyiv's forces make limited gains in a high-stakes counteroffensive against Russian troops.

"We are convening in a historic meeting of the EU foreign ministers here in Ukraine, candidate country and future member of the EU," the bloc's foreign policy chief, Josep Borrell, said in a statement.

The purpose of the meeting was to "express our solidarity and support to the Ukrainian people," he said, acknowledging that the gathering "does not have the aim of reaching concrete conclusions and decisions."

Ukraine's Foreign Minister Dmytro Kuleba hailed the discussions as an important signal of European support.

"For the first time ever the foreign affairs council is going to sit down outside of its current borders – outside the borders of the European Union – but within future borders of the European Union," Kuleba told reporters alongside Borrell.

The EU's 27 nations have remained broadly united through the 19 months of war in their support for Ukraine, hitting Russia with 11 rounds of sanctions and spending billions of euros on arms for Kyiv.

'Lasting support'

But there are growing fears of cracks appearing within the bloc as concern also rises over the support of key backer the United States.

Hungary, Russia's closest ally in the EU, could now be joined by Slovakia as a potential block to more backing as populist Robert Fico pushes for power in Bratislava after winning elections this weekend.

There have also been tensions between Kyiv and some of its most strident backers on the EU's eastern edge – most notably Poland – over the influx of Ukrainian grain onto their markets.

France's top diplomat Catherine Colonna appeared to address the concerns, saying the meeting was a signal to Moscow of the bloc's determination to support Ukraine over the long term.

"It is a demonstration of our resolute and lasting support for Ukraine, until it can win," she told reporters.

"It is also a message to Russia that it should not count on our fatigue. We will be there for a long time to come."

The Kremlin, which anticipated a lightning-fast takeover of Ukraine, is counting on Western countries tiring in their support for Kyiv, and predicted Monday that fatigue over Ukraine "will grow."

'Winter protection plan'

Germany's Foreign Minister Annalena Baerbock called for the creation of a strategy to insulate Ukraine from the fallout of a feared campaign of Russian strikes on Ukraine's energy grid in the coming months as temperatures drop.

"Ukraine needs a winter protection plan of air defense, generators and a strengthening of the energy supply," she said in Kyiv.

"We saw last winter the brutal way in which the Russian president wages this war, with targeted attacks on critical infrastructure such as power plants."

Ukrainian authorities say Russia has launched systemic aerial attacks on Ukraine's energy infrastructure, a strategy that last year left millions without heating or water.

The foreign ministers of Hungary, Poland and Latvia did not attend the summit, a Ukrainian government official told AFP on condition of anonymity. The Polish and Latvian representatives were ill, the official said.

Russian President Vladimir Putin ordered troops into Ukraine in February 2022 and his army swept quickly through large swathes of the south and east of the country but were beat back from the north.

In June, Kyiv launched a long-awaited counteroffensive but has acknowledged slow progress as its forces encounter deep lines of heavily fortified Russian defenses.

"With every village, every meter that Ukraine liberates, with every meter where it is saving its people's lives, it also paves its way into the European Union," Baerbock said.

On Monday, Ukraine's Interior Minister Igor Klymenko said Russia shelled the city of Kherson in the south, critically wounding a civilian and two police.

Police also said a civilian was killed by Russian fire in the nearly encircled town of Avdiivka in the war-battered Donetsk region in the east.

Separately, Kyiv's intelligence service said that Ukraine's drones at the weekend had struck a plant that produces cruise missiles in the western region of Smolensk.