A long-awaited free trade agreement expanding the economic ties between Ukraine and the European Union came into force on Friday, setting the stage for strife with Russia.
The free trade deal grants Ukraine tariff-free access to the EU's giant market and is expected to boost the country's struggling economy. The 28-country bloc is Ukraine's largest trading partner, accounting for more than a third of its trade, according to EU data.
"The change will not occur over night, it will require work and investment," EU Trade Commissioner Cecilia Malmstrom said Thursday, while adding that the deal creates "unique opportunities for Ukraine to stabilise, diversify and develop its economy."
Under the agreement, the EU will help Kiev adapt to EU standards and rules in areas such as competition, public procurement and intellectual property rights.
But Russia has long been critical of the trade pact, amid concerns that it could negatively impact its own economy.
In a bid to address Moscow's concerns, Kiev and Brussels had agreed to delay the implementation of the free trade agreement by a year and hold talks with Russian officials. But the three sides were not able to find common ground, despite more than 20 three-way meetings.
Moscow has now started implementing punitive trade measures against Ukraine, although some Russian officials have argued that they are not linked to the EU-Ukraine free trade deal.
The agreement is at the heart of the current crisis in Ukraine.
A first attempt to finalize the deal had failed in 2013, triggering protests in Kiev that led to the ouster of Ukraine's pro-Russian president, followed by Russia's annexation of Ukraine's Crimea peninsula and a pro-Russian separatist uprising in eastern Ukraine.
Relations between the EU and Moscow have since fallen to their lowest level after the Cold War.