(Adds Tusk, Polish PM Szydlo)
By Gabriela Baczynska and Robert-Jan Bartunek
BRUSSELS, Dec 15 (Reuters) - European Union leaders agreed on Thursday to spell out limits to a landmark cooperation accord with Ukraine to address Dutch concerns and prevent the landmark deal from unravelling.
The so-called association agreement establishes closer political ties and aims to free up trade between Ukraine and the bloc as the former Soviet republic moves closer to western Europe and away from Moscow's orbit.
But the leaders agreed it did not make Ukraine a candidate for EU membership, and did not entitle Kiev to financial aid or military assistance from the bloc. Neither did it give Ukrainians the right to live and work in the 28-nation union.
By imposing caveats on the deal, Dutch Prime Minister Mark Rutte aims to ease the concerns of his voters, who rejected it in a referendum in April.
Failure to secure the agreement of his fellow EU leaders would effectively have doomed the accord, which Rutte said would have been "an enormous present for Russia".
He told reporters: "It is in the Dutch interest that Europe is strong in its relationship with Russia, with Russia being increasingly aggressive in its foreign policy."
The Netherlands is the only EU country that has yet to ratify the deal, which would become void without its endorsement. Rutte will now take Thursday's agreement to the Dutch parliament in an attempt to win its approval and overwrite the referendum result.
"Now the responsibility lies with the Netherlands. The ratification is important not only for Ukraine, but also for Europe's geopolitical standing and credibility," said Donald Tusk, the chair of EU leaders' meetings.
Poland and some other EU states were annoyed with the Dutch demands but in the end decided they did not want to jeopardise the entire agreement.
"We have saved the agreement with Ukraine and everything points to the fact now that it will be ratified in full," said Polish Prime Minister Beata Szydlo.
The leaders also spelt out the need for Ukraine to fight endemic corruption.
The accord has huge importance for Ukraine as a symbol of its future direction, 25 years after the collapse of the Soviet Union. A pro-Russian president in Kiev was toppled by mass street protests in early 2014 after he tried to ditch the EU agreement in favour of a deal with Moscow.
Russia responded by annexing Ukraine's peninsula of Crimea and went on to back a separatist rebellion in eastern Ukraine, a conflict that has killed nearly 10,000 people to date.
This has sent ties between Moscow and the EU to their lowest in decades, aggravating other disputes over trade, human rights and security, including the war in Syria.
The bloc slapped sanctions on Russia over Ukraine, and the EU leaders agreed on Thursday to extend the main economic measures until mid-2017.
(Additional reporting by Alastair Macdonald, Writing by Gabriela Baczynska; Editing by Mark Trevelyan and Elizabeth Piper)
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