European Union leaders today pushed Ukraine to step up its battle against corruption after the 28 -nation bloc agreed to ratify a landmark cooperation deal.
The high-profile summit in Kiev comes as Ukraine has taken a series of steps to move closer to the EU in the face of hostility from its giant former Soviet master Moscow.
"Corruption is one of the biggest problems of this country," European Commission chief Jean-Claude Juncker said.
"What we are asking is to increase the fight against corruption because corruption is undermining all the efforts of this great nation."
Ahead of the summit, EU states on Tuesday said they had formally decided to conclude the ratification of the Association Agreement with Ukraine, effective September 1.
The announcement marks the latest chapter in the tortured history of a deal that played a central role in sparking the crisis in Ukraine that has driven a deep wedge between Moscow and the West.
In late 2013 Ukraine's then-president Viktor Yanukovych backed out of the association agreement under pressure from Russia, sparking mass pro-EU protests which led to his toppling months later.
Moscow in turn annexed Crimea in 2014 and backed pro- Russian rebels in eastern Ukraine where more than 10,000 people have since died in fighting with government forces.
The European Union and Ukraine agreed the accord in late 2014 when EU-Moscow relations were at their lowest point for decades.
EU association agreements are often the prelude to later membership and are meant to bring a country's political, economic and civil society norms into line with those of the bloc.
But faced with a hostile Moscow and as concerns swirl over backsliding by Kiev's Western leadership, the EU appears hesitant to set Ukraine on a fast track to full membership.
Last month Ukrainians celebrated the start of visa-free travel to Europe and President Petro Poroshenko said Ukraine intends to join the European Union Customs Union, integrate into the Schengen Area and become part of a proposed European energy union.
"It is important already today to begin developing a roadmap to achieve our aspirations," Poroshenko said.
Despite some high-profile efforts to battle corruption, critics say that Ukraine's authorities have failed to tackle the deeply rooted influence of politically-connected oligarchs.
Those appointed to fight the rampant graft in the country have faced repeated hurdles, and the EU has criticised a law targeting non-governmental organisations trying to curb corruption.