The bloc’s goal is to cement closer ties with Ukraine by concluding a political and economic pact, known as an association agreement, at a summit in November that will feature heads of government from a region of Europe where Brussels and Moscow are butting heads.
The EU’s two most senior officials – José Manuel Barroso, the European Commission president, and Herman Van Rompuy, the European Council president – expressed their “determination in moving forward” with the agreement after meeting Ukraine’s president, Viktor Yanukovich, at the UN General Assembly in New York on Tuesday.
EU member states agreed in a private meeting on Monday to sweeten their offer so that Ukraine could enjoy many of the pact’s benefits, including trade liberalisation, as soon as it is signed.
Under the original plan, Ukraine would have had to wait for all 28 EU parliaments – as well its own – to endorse the text, a process that diplomats say could drag on for a year or longer.
Addressing the UN General Assembly on Wednesday, Mr Yanukovich signalled his approval, describing Ukraine’s “Euro-integration aspirations” as “a decisive vector for the country’s development”.
Mr Yanukovich is also now entertaining a compromise, according to EU officials, that could result in the release of opposition leader Yulia Tymoshenko to seek medical treatment in Germany, but not a formal pardon.
Her imprisonment on controversial corruption charges two years ago has thwarted closer ties with the west.
In spite of lingering concerns about the Tymoshenko case and the Ukrainian legal system, the EU has intensified its outreach to the country – as well as Georgia and Moldova – in response to increasingly aggressive moves by Russia to keep them in its own orbit.
Moscow stunned European diplomats this month when it prevailed on Armenia to abruptly drop a long-negotiated association agreement to instead sign up to a fledgling Eurasian customs union that Russia is developing with Kazakhstan and Belarus as a counterweight to the EU.
The Kremlin has been particularly harsh towards Ukraine, the largest country in the region.
An adviser to President Vladimir Putin of Russia warned Kiev this weekend that signing the EU pact would damage trade relations with Moscow, its biggest energy supplier, and could ultimately force a debt default that would require a €35 billion ($47 billion) bailout.
“If Ukraine signs this association agreement [with the EU], and after this faces a worsening trade balance, then the question arises: who will pay for Ukraine’s imminent default?” Sergey Glazyev, the Putin adviser, asked.
During his annual state-of-the-union address, Mr Barroso insisted that the EU would not tolerate such tactics.
“We cannot accept any attempt to limit these countries’ own sovereign choices,” Mr Barroso said.
“We cannot turn our back on them.”
Stefan Füle, the EU’s enlargement commissioner, has argued that the EU offer does not represent “a choice between Moscow and Brussels,” saying, “we want our partners to have good relations and co-operation with Russia”.
But the commission has also been sharpening its sales pitch.
On Wednesday it proposed opening the EU market to Moldovan wines, just days after Russia prohibited them, citing health concerns.
“In some aspects, the Russian pressure has helped us,” an EU official said.
In spite of the determination to win over Ukraine, particularly among eastern member states such as Poland and Lithuania that are still wary of Russian domination, others continue to harbour concerns about a formerly communist country with a history of corruption and selective justice.
The EU set 11 benchmarks for reform last December that Ukraine was to satisfy in order to seal the accession agreement.
Mr Füle recently praised Kiev’s “unprecedented” progress.
But in an editorial published in a Ukrainian paper last week, David Lidington, the UK’s Europe minister, took a more sober view, noting that the UK had still not decided how it would vote on the pact.
“Our decision will be based on an objective assessment of whether the changes introduced provide sufficient evidence of a genuine commitment to reform,” Mr Lidington wrote.
“We very much hope that we will be able to launch a new phase of EU-Ukraine partnership at Vilnius. But we need to be convinced that it is really going to work.”
Mr Barroso and Mr Van Rompuy also reminded Mr Yanukovich at the UN that the association agreement still hinges on Ms Tymoshenko’s release as they urged him to “make tangible progress” on reform.