SEVASTOPOL, Ukraine >> Moscow mounted pressure on Ukraine Saturday, with Russia’s foreign minister denouncing the new Ukrainian authorities as puppets of armed radicals and pro-Russia forces in Crimea trying to flush Ukrainian soldiers out of the few military bases still under their control.

The regional parliament in Crimea has set a March 16 referendum on leaving Ukraine to join Russia, and senior lawmakers in Moscow said they would support the move, ignoring sanctions threats and warnings from U.S. President Barack Obama that the vote would violate international law.

The strategic peninsula in southern Ukraine has become the flashpoint in the battle for Ukraine, where three months of protests sent President Viktor Yanukovych fleeing to Russia. A majority of people in Crimea identify with Russia, and Moscow has a major naval base on the Black Sea.

While the U.S. and the EU urged Russia to engage in dialogue with new Ukrainian authorities who came to power on the wave of protests that sent President Viktor Yanukovych fleeing to Russia, the Kremlin has refused to do so, denouncing the change of power in Ukraine as “unconstitutional coup.”

Russia’s Foreign Minister Sergey Lavrov said Saturday that Moscow sees no sense in having a dialogue with Ukraine’s new authorities because, in his view, they kowtow to radical nationalists.

“The so-called interim government isn’t independent, it depends, to our great regret, on radical nationalists who have seized power with arms,” he said at a news conference.  He said that nationalist groups use “intimidation and terror” to control Ukraine.

Meanwhile in Crimea, pro-Russia soldiers late Friday tried to take over a Ukrainian base in a tense standoff that lasted for several hours.

Lt. Col. Vitaly Onishchenko, deputy commander of the base, said three dozen men wearing unmarked camouflage uniforms arrived late Friday. While one group climbed over a wall on one side of the base, another crashed a heavy military truck through the gates, Onishchenko said.

He said Saturday that they turned off power, cut telephone lines and demanded that about 100 Ukrainian troops, who barricaded themselves into one of the base buildings, surrender their weapons and swear allegiance to Russia. The invaders left around midnight.

No shots were fired in and no injuries were reported, but the incident reflected tensions running high on the Black Sea peninsula. In the week since Russia seized control of Crimea, Russian troops have been neutralizing and disarming Ukrainian military bases there. Some Ukrainian units, however, have refused to give up. Crimea’s new leader has said pro-Russian forces numbering more than 11,000 now control all access to the region and have blockaded all military bases that haven’t yet surrendered.

Russia has denied that its forces are active in Crimea, describing the troops who wear green uniforms without insignia as local “self-defense forces.” But many of the troops, who are armed with advanced heavy weaponry, are being transported by vehicles with Russian license plates.

Onishchenko said the troops who assailed his base were clearly Russian.

“These were Russian servicemen specially ordered,” he said. “Their watches were set to Moscow time. They spoke with Russian accents and they didn’t hide their allegiance to the Russian Federation. But they didn’t have any distinguishing marks (on their uniforms). Without doubt, this was a Russian action.”

Russia’s President Vladimir Putin said that Moscow has no intention of annexing Crimea, but says its people have the right to determine the region’s status in a referendum.

The Crimean referendum has been denounced by Ukraine’s new government, and U.S. President Barack Obama says it would violate international law. The U.S. moved Thursday to impose its first sanctions on Russians involved in the military occupation of Crimea.

Speaking on BBC on Saturday, NATO Secretary-General Anders Fogh Rasmussen said that while there is no military response to the recent events of Crimea, the crisis was a reminder that there are treats to European security and stability.

“I do believe that politicians all over NATO will now rethink the whole thing about investment in security and defense,” he told the BBC. “Obviously, defense comes at a cost but insecurity is much more expensive.”

Mike Eckel in Kiev, Vladimir Isachenkov in Moscow and Danica Kirka in London contributed to this report