The EU on Friday pledged to support Ukraine "every step of the way" in its quest for bloc membership as top officials gathered in Kyiv for a highly symbolic summit.
Ukrainian President Volodymyr Zelensky, who is hosting the meeting, is pressing the bloc for speedy membership as it battles to defeat a nearly year-long Russian invasion.
The EU granted candidate status to Ukraine last June, but the path to full membership is likely to be fraught and could take years.
EU chief Charles Michel announced his arrival in the Ukrainian capital as air raid sirens sounded, vowing that there will be "no let up in our resolve."
"We will also support you every step of the way on your journey to the EU," Michel tweeted.
The bloc's chief Ursula von der Leyen and the EU's most senior diplomat, Josep Borrell, are also in Kyiv for the summit.
Zelensky said following talks with von der Leyen on Thursday that Ukraine "deserves to start negotiations on EU membership this year".
"Only together a strong Ukraine and a strong European Union can protect the life we value."
Von der Leyen welcomed steps taken by Ukraine for membership and said the EU was looking to finalise new sanctions against Russia by February 24, the first anniversary of the invasion.
Kremlin shrugs off sanctions
Putin insists Russia is weathering the barrage of sanctions imposed by Ukraine's Western allies and said his forces will continue to fight regardless of the penalties.
But von der Leyen said that sanctions were already "eroding" Russia's economy, "throwing it back by a generation".
She estimated that an oil price cap introduced in December was costing Moscow around 160 million euros every day.
But Zelensky said the West needed to do more -- and quickly -- and claimed Russia was adapting to the Western measures.
Now an EU ban on Russian oil products like diesel, gasoline and jet fuel, is set to come into effect on Sunday alongside a G7 price cap on these products.
But the Kremlin warned Friday that the measures would destabilise the markets more broadly rather than only impacting Russia.
"This will lead to a further imbalance of the international energy markets, but we are taking measures to hedge our interests against the risks associated," Kremlin spokesman Dmitry Peskov told reporters.
Graft is a key European concern and Ukraine has recently widened efforts to tackle corruption with officials warning of an ongoing fight against an "internal enemy".
The latest measures saw highly publicised raids by the security services targeting residences of an oligarch with deep political connections and a former interior minister.
Fears of fresh offensive
Von der Leyen tweeted that Ukraine was "taking notable steps forward to meet our recommendations, while at the same time fighting an invasion".
"We have never been closer," she said, noting that the EU was "working on extending tariff-free access to our market".
Enacting reforms is also crucial for Kyiv to appease its backers' concerns for more financial support but also military aid.
Kyiv has secured promises from the West for deliveries of modern battle tanks to fight Russian forces and is now asking for long-range missiles and fighter jets.
A German government spokesman said Friday that Berlin has authorised Leopard 1 tanks to be sent to Ukraine, making good on the announcement last month to send the weapons that came after months of deliberations.
Despite a steady flow of arms and ammunition, Russian forces are pressing Ukrainian troops in the eastern Donetsk region, now the epicentre of fighting.
Moscow has been trying to seize control of Bakhmut in the industrial region for months in what has become the longest and bloodiest battle of the invasion.
But Zelensky warned with von der Leyen that the Kremlin is consolidating its forces for a fresh offensive.
Russia is "preparing to try to take revenge, not only against Ukraine, but against a free Europe and the free world", he told a press conference on Thursday.
