BRUSSELS, March 18 (Xinhua) -- The top leaders of the European Union (EU) on Tuesday reiterated the referendum in Crimea is "illegal".
"The sovereignty, territorial integrity and independence of Ukraine must be respected," European Council President Herman Van Rompuy and European Commission President Jose Manuel Barroso said in a joint statement.
"The European Union does neither recognize the illegal and illegitimate referendum in Crimea nor its outcome," said the EU leaders.
They added that the EU does not and will not recognize the "annexation" of Crimea and Sevastopol to Russia.
The EU leaders said the European Council will discuss the situation in Ukraine at its meeting this week and agree on a united European response.
Earlier in the day, Russian President Vladimir Putin and Crimean leaders signed a treaty to make Crimea and the city of Sevastopol part of Russian territory.
The treaty came one day after the Crimean parliament's decision to declare independence from Ukraine, with official results from a referendum showing nearly 97 percent of Crimean voters chose to join Russia.
As for Sunday's referendum during which an overwhelming majority of Crimeans voted to join Russia, Putin said Crimea acted under the UN Chapter which declares the right of a nation for self-determination.
Meanwhile, the Russian leader called situation in Ukraine a mirror of what happened in the world after the collapse of the bi-polar system. He blamed the U.S. exceptionalism and its use of forces against sovereign states ignoring the UN and the UN Security Council.
"They brought no democracy and freedom but chaos and violence ... We were cheated repeatedly by the West," he said.