European Council President Charles Michel declared during a visit to Kyiv on Thursday that "we must spare no effort" in helping Ukraine join the 27-member bloc.
Michel met President Volodymyr Zelenskiy and delivered an address to parliament hailing the country's resilience amid Russia's invasion and saying "Ukraine is the EU and the EU is Ukraine."
Brussels granted Kyiv membership candidate status last June, just months after Moscow's Feb. 24 assault.
"We must spare no effort to turn this promise as fast as we can into reality," Michel said, according to a transcript of the address.
"I dream that one day, I hope soon, a Ukrainian will hold my job as President of the European Council, or as President of the European Parliament, or the Commission."
Michel's visit, two weeks before an EU-Ukraine summit on Feb. 3, coincided with fresh pledges by Ukraine's allies of hundreds of millions of dollars in new weaponry. But uncertainty swirled around whether heavy tanks would be provided.
Michel said a day earlier he was personally in favour of the West providing tanks to Ukraine. On Thursday the United States and Germany sought to resolve a stand-off that has so far prevented the West from sending the modern tanks Kyiv says it needs to help turn the tide against Russian forces.
"We will work with member states to make this happen," an EU official told Reuters. "Ahead of the EU-Ukraine summit, it's best to pinpoint with Zelenskiy what is most urgently needed and where we can boost our support."
The official also said Kyiv would need to improve its rule of law before joining the bloc.
In a joint briefing with Michel, Zelenskiy urged Ukraine's allies to supply Kyiv with more arms as soon as possible, saying it would help guarantee European security.
He added that negotiations on Ukrainian membership in the bloc should begin this year.
"For this we have all the necessary preconditions," he said. "We have great motivation, and a great desire - we are moving forward."
Ukraine's parliament has passed all the legislation sought by the EU before the start of accession talks, but implementing those laws is expected to be a long road.
The EU is slated to provide Ukraine 18 billion euros in financial support in 2023 and is also mulling a tenth package of sanctions against Russia.
It is also aiding investigations into alleged war crimes by Russian troops and supports creating an international tribunal to prosecute Russia's political and military leadership for attacking Ukraine.
(Reporting by Dan Peleschuk and Olena Harmash in Kyiv, additional reporting by Gabriela Baczynska in Brussels, Writing by Dan Peleschuk and Gabriela Baczynska, Editing by Mark Heinrich and Deepa Babington)