A cat sits on a bench in Red Square in central Moscow, Russia, on Sept

22. (Vasily Maximov/AFP/Getty Images)

Russian forces have seized the Crimea region of Ukraine by forcibly arresting the new national government and the country’s most powerful opposition figures, according to the United Nations.

The ousted parliament and its unelected prime minister were put on Ukrainian territory with armored vehicles and other heavy weapons Tuesday, the world body said. U.N. and Kyiv-based officials say that 5,000 or more Russian soldiers are inside Ukraine’s territorial airspace. More than 1,800 have mounted ground attacks, according to Ukraine’s Interior Ministry, which has stated that up to 500 Russian troops are in the region.

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Russia has rejected the assertion by the United Nations and other Western countries that it has seized control of Crimea because it believes the people of the region should decide their future.

Citing a statement by Russian Deputy Foreign Minister Grigory Karasin, Amnesty International said that a group of “armed men dressed all in black” were conducting “a kicking and chanting operation” in Crimea.

Earlier Tuesday, before the takeover of the Crimean capital of Simferopol, Moscow sent more than 100,000 recruits to hands-on training for the 2014 military campaign in the country, the Russian Defense Ministry said. The International Institute for Strategic Studies reported that more than 100,000 irregulars were telephoned before being told they had to take part in one of Russia’s new war games.

In Simferopol, the law enforcement headquarters said, there had been no sightings of Russian military vehicles or troops for two hours Tuesday, local news reports said.

By late Tuesday, the the armed men refused to take an oath of allegiance to the new authorities in Crimea, demanding that they hand over the Crimean Parliament’s documents, RIA Novosti reported.

“They aren’t accepting the authorities [in Crimea],” a serviceman told Channel One, an independent television channel in Russia. “This is exactly what happened at Maidan, and now again in Crimea.” A pro-government journalist, Irina Volkova, said that 40 students from Moscow’s Far Eastern Economic University had been arrested overnight.

James Carden, a former CIA officer who has advised Ukrainian opposition leaders, said in a report that U.S. officials had tied Russia’s decisions to the Crimea seizure directly to President Vladimir Putin’s reaction to the Obama administration’s rejection of a Russian proposal late last month to consider the Crimea option for Ukraine’s presidential election.

Carden, who has met with ousted Ukrainian President Viktor Yanukovych twice in recent months, said the Russian government “had developed an important sense of hesitation” over clearing its loyalists from Crimea.

A model’s statement of the lesson she wants to teach children about Russia’s seizing of the Crimea. (Carol Muller/The Washington Post)

“The Russian government is in a tight spot because the Ukrainians have around them a very weak coalition of constitutional and popular officials that they can rely on to oppose Putin’s outrageous proposals, including grabbing Crimea,” Carden, now a senior fellow at the Centre for Strategic and International Studies in Washington, wrote in a report for Carnegie Endowment.

Putin, who traditionally regarded the Ukrainian crisis as an internal problem to be resolved at home, painted Ukraine’s new leadership as illegitimate, a Russian Interfax news agency quoted Russian President Dmitri Medvedev as saying in an interview published Monday.

“The international community is showing a clear and organized will to return the Ukrainian nation to its country,” he said. “But the new regime, replacing that of President Viktor Yanukovych, goes against the will of the vast majority of the population, of course including those of my compatriots living in Ukraine.”

Russian forces have seized the Crimean Parliament, the regional administration building and defense facilities as well as airports and ports that work under Ukrainian control, while imposing trade sanctions and refusing to provide police permits. The United States and Britain have threatened to impose sanctions of their own.

But with the European Union immersed in an internal debate on whether to take further measures against Russia for mass violations of human rights and media freedom, Russia’s military intervention in Crimea represents yet another crucial test of their resolve in the region. The E.U. security and foreign ministers meeting Wednesday in Vilnius, Lithuania, may address the Ukrainian crisis, but the United States and Russia are unlikely to agree on any joint response.

The previous Russian-led occupation of Crimea began in February, following Yanukovych’s decision to scrap a deal with the European Union and turn toward Russia for loans and money. Russia negotiated an appropriately conditional agreement with the E.U., but Yanukovych again banned public protests.