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Ukrainian Foreign Minister Andriy Deshchytsia addresses a news conference during a NATO foreign ministers meeting at the Alliance headquarters in BrusselsReuters

Ukrainian Foreign Minister Andriy Deshchytsia has said that Ukraine is to file a lawsuit against Russia at the International Court of Justice over the annexation of the Crimea region.

"We consider Crimea part of Ukraine, we are planning to file lawsuits in international courts against Russia and against Russia's actions in Crimea," Deshchytsia said at a press conference following a meeting with Nato in Brussels.

Although Deshchytsia did not confirm when the lawsuit would be filed, he suggested that it would be submitted to the United Nation's main judicial body, the International Court of Justice.

"We believe that with international support, we will be able to get Crimea back to Ukraine," Deshchytsia said.

"We are gathering documents now, it may take some time," he added.

The diplomat's revelation comes after Nato foreign ministers pledged beef up Ukraine's security in the face of what they described as Russia's challenge to freedom and peace in Europe.

The 28-member alliance also said it would suspend all civilian and military cooperation with Moscow over russia's "illegal military intervention" in Ukraine.

"We do not recognise Russia's illegal and illegitimate attempt to annex Crimea," the foreign ministers said after a closed-door meeting at Nato headquarters in Brussels.

The Russian State Duma this week voted to approve President Vladimir Putin's proposal to abolish three agreements with Ukraine over Russia Black Sea fleet status.

Ukraine Justice Minister Pavlo Petrenko however said that Ukraine would continue to recognise the agreements and demand that Russia continue to provide natural gas price discounts in return for the rental of Sevastopol naval base.