SEVASTOPOL, Ukraine (AP) — Dozens of military trucks transporting heavily armed soldiers rumbled over Crimea’s rutted roads Saturday as Russia reinforced its armed presence on the disputed peninsula in the Black Sea.  Moscow’s foreign minister ruled out any dialogue with Ukraine’s new authorities, whom he dismissed as the puppets of extremists.

The Russians have denied their armed forces are active in Crimea, but an Associated Press reporter trailed one military convoy Saturday afternoon from 25 miles (40 kilometers) west of Feodosia to a military airfield at Gvardeiskoe north of Simferopol, over which a Russian flag flew.

Some of the army green vehicles had Russian license plates and numbers indicating that they were from the Moscow region. Some towed mobile kitchens and what appeared to be mobile medical equipment.

The strategic peninsula in southern Ukraine has become the flashpoint in the battle for Ukraine, where three months of protests sparked by President Victor Yanukovych’s decision to ditch a significant treaty with the 28-nation European Union after strong pressure from Russia led to his downfall. A majority of people in Crimea identify with Russia, and Moscow’s Black Sea Fleet is based in Sevastopol, as is Ukraine’s.

Vladislav Seleznyov, a Crimean-based spokesman for the Ukrainian armed forces, told AP that witnesses had reported seeing amphibious military ships unloading around 200 military vehicles in eastern Crimea on Friday night after apparently having crossed the Straits of Kerch, which separates Crimea from Russian territory.

“Neither the equipment, nor the paratroopers have insignia that identify them as Russian, but we have no doubt as to their allegiance,” Seleznyov said.

The amphibious operation appeared to be one of the largest movements of Russian military forces since they appeared in Crimea a week ago.

Seleznyov also said a convoy of more than 60 military trucks was spotted Saturday heading from Feodosia toward Simferopol, the regional capital. An AP reporter caught up with the convoy and trailed it to a Russian-controlled airfield. In the rear of the vehicles, heavily armed soldiers could be seen, though none appeared to have identifying badges or insignia. Soldiers spat at the reporters following them.

A small plane belonging to the Ukrainian border guards was fired on by “extremists” using automatic weapons as it flew near the administrative border of Crimea, but took evasive maneuvers and escaped unscathed, the Interfax news agency reported, quoting Ukrainian officials.

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 President Barack Obama that the vote would violate international law.

While the U.S. and the EU urged Russia to engage in dialogue with new Ukrainian authorities, the Kremlin has refused to do so, denouncing the change of power in Ukraine as an “unconstitutional coup.”

Russian Foreign Minister Sergey Lavrov said Moscow sees no sense in talking with Ukraine’s new authorities because, in his view, they kowtow to radical nationalists.

Russian President Vladimir Putin has said that Moscow has no intention of annexing Crimea, but that 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. The U.S. moved Thursday to impose its first sanctions on Russians involved in the military occupation of Crimea.

An international military mission composed of officers from the U.S. and 28 other nations tried again Saturday to enter Crimea, but it was turned back around the town of Armiansk by armed men.

An AP reporter traveling with the 54 observers from the Organization for Security and Cooperation in Europe said that after the group had stopped, the armed men fired bursts of automatic weapons fire to halt other unidentified vehicles. No injuries were reported.  

In Simferopol, meanwhile, a public ceremony was held for the swearing-in of the first unit in the pro-Russia “Military Forces of the Autonomous Republic of Crimea.” About 30 men armed with AK-47s, and another 20 or so unarmed, turned out. They ranged in age from teenagers to a man who looked to be about 60. They were sworn in at a park in front of an eternal flame to those killed in World War II.

Sergei Aksyonov, the Crimean prime minister, came to the ceremony and was greeted by the soldiers with shouts of “Commander!”

He said their main role, at least until the referendum, would be to “keep the peace.” He said he didn’t foresee any fighting with the Ukrainian soldiers still at bases in Crimea.

In the week since Russia seized control of Crimea, Russian troops have been disarming Ukrainian military bases there. Some Ukrainian units, however, have refused to give up. Aksyonov 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.

On Friday evening, pro-Russia soldiers tried to take over another Ukrainian base in Sevastopol, resulting in a tense standoff that lasted for several hours.