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Ukraine's government condemned referendums in eastern Ukraine as a "farce" on Monday, as separatists from the pro-Moscow regions declared independence and asked to join Russia.

Organizers said 89 percent of those who cast ballots Sunday in the Donetsk region and about 96 percent of those who turned out in Luhansk voted for sovereignty for the sprawling areas that lie along Russia's border and form Ukraine's industrial heartland. Donetsk has about 4.4 million people, and Luhansk has 2.2 million.

The results were seized upon by separatists who pushed for further autonomy from Kyiv and annexation by Russia.

On Monday, the self-declared Donetsk People's Republic (DPR) declared the region independent and signaled a desire to follow Crimea in being annexed by Moscow.

"Based on the will of the DPR and to restore historic justice, we ask the Russian Federation to consider the question of entry of the DPR into the Russian Federation," said Denis Pushilin, chairman of the DPR, said in a televised press conference.

The pro-Russian mayor of Slovyansk even invited Russian troops into the region to provide stability.

Likewise, pro-Russian leaders in the Luhansk region also called for autonomy, announcing its independence at a public rally.

But Kyiv sought Monday to delegitimize the regional vote.

Even before the results were announced, Ukraine's Foreign Ministry called the referendums a "criminal farce." The U.S. and other Western governments said they wouldn't recognize the outcome and threatened further economic penalties.

In response to the Ukrainian government's reaction to the referendums, the Russian Foreign Ministry said on Monday that Kyiv was acting with a "criminal" lack of readiness to engage in dialogue with eastern Ukraine. It called again for the Ukrainian government to initiate talks with the breakaway regions.

Western leaders, faced with Russian assertiveness not seen since the Cold War, have suggested more sanctions in the key areas of energy, financial services and engineering if Moscow disrupts a presidential election planned in Ukraine on May 25.

The European Union, which has called the referendum illegal, has prepared a list of 13 people and two Crimean companies active in the energy sector that ministers are likely to add to the EU sanctions list, EU diplomats said.

But the EU will remain far behind the United States in the severity of the sanctions it has imposed on Russia. Some European governments fear tough trade sanctions on Russia could undermine their economies, which are just recovering from the financial crisis, and provoke Russian retaliation.