Ukraine's military admitted Monday that pro-Russian troops have surrounded or taken over "practically all" its military facilities in Crimea - a move that Russia's foreign minister defended as a necessary protection for the ethnic Russians on the Black Sea peninsula.
"This is a question of defending our citizens and compatriots, ensuring human rights, especially the right to life," Russian Foreign Minister Sergey Lavrov said in Geneva, where he was attending U.N. meetings.
There have been no reports, however, of any hostilities toward Russian-speaking in Ukraine during the country's four months of political upheaval.
The Russian Foreign Ministry also issued a statement saying that Moscow believes Ukraine must honor its Feb. 21 agreement to form a new national unity government.
In Kiev, Ukraine's new prime minister admitted his country had "no military options on the table" to reverse Russia's military move into its Crimea region.
While Prime Minister Arseniy Yatsenyuk appealed for outside help and insisted that Crimea still remained part of his country, European foreign ministers held an emergency meeting on a joint response to Russia's military move that could include economic sanctions.
"Any attempt of Russia to grab Crimea will have no success at all. Give us some time," Yatsenyuk said at a news conference with British Foreign Secretary William Hague.
But he added that "for today" there were "no military options on the table." He said his country was "urgently" asking for economic and political support from other countries.
New reports of Russian moves came in rapid succession Monday. In addition to seizing barracks and border posts, troops also controlled a ferry terminal in the Ukrainian city of Kerch, just 20 kilometers (12 miles) across the water from Russia. That intensified fears in Kiev that Moscow will send even more troops into the peninsula via that route.
The soldiers at the terminal refused to identify themselves Monday, but they spoke Russian and their vehicles had Russian license plates.
In the meantime, Russian forces were clearly cementing their control over strategic Crimea, home to 2 million mostly Russian-speaking people and landlord for Russia's critical Black Sea Fleet.
Border guards spokesman Sergei Astakhov said the Russians were demanding that Ukrainians transfer their allegiance to Crimea's new pro-Russian local government.
"The Russians are behaving very aggressively, they came in by breaking down doors, knocking out windows, cutting off every communication," he said.
He said four Russian military ships, 13 helicopters and 8 transport planes had arrived in Crimea in violation of agreements that permit Russian to keep its naval base at the Crimean port of Sevastopol.
Now, fears in the Ukrainian capital of Kiev and beyond are that Russia might seek to expand its control by targeting and seizing other parts of Ukraine, especially in its pro-Russian east.
"The world cannot just allow this to happen," Hague said, but he ruled out any military action. "The U.K is not discussing military options. Our concentration is on diplomatic and economic pressure."
"Crisis diplomacy is not a weakness, but it is now more important than ever for us not to fall into the abyss of a military escalation, not to blunder into this abyss," German Foreign Minister Frank-Walter Steinmeier said.
Market reaction to the Russian invasion of Crimea was immediate Monday. In European trading, gold and oil rose while the euro and stock markets fell. The greatest impact was felt in Moscow, where the main RTS index was down 12 percent at 1,115 and the dollar spiked to an all-time high of 37 rubles.
Russia's central bank hiked its main interest rate 1.5 percentage points Monday to 7 percent, trying to stem financial outflows.
Gazprom, the Russian energy giant, was also big loser, its share price down 13 percent as investors worried about how it would get its gas to Europe if hostilities kept up, since much of it goes through Ukrainian pipelines.
Tension between Ukraine and Moscow rose sharply after Ukraine's pro-Russian President Viktor Yanukovych was pushed out by a protest movement made up of people who wanted closer ties with the European Union.
Yanukovych fled to Russia last month after more than 80 demonstrators were killed near Kiev's central square but insists he is still president.
Since then, troops that Ukraine says are Russian soldiers have moved into Crimea, patrolling airports, smashing equipment at an air base and besieging Ukrainian military installations.
Outrage over Russia's military moves has mounted in world capitals, with U.S. Secretary of State John Kerry calling on President Vladimir Putin to pull back from "an incredible act of aggression." Kerry is to travel to Ukraine on Tuesday.
I will be headed to Kyiv, Ukraine tomorrow night for discussions there Tuesday.— John Kerry (@JohnKerry) March 2, 2014
Putin has defied calls from the West to pull back his troops, insisting that Russia has a right to protect its interests and those of Russian-speakers in Crimea and elsewhere in Ukraine. His confidence is matched by the knowledge that Ukraine's 46 million people have divided loyalties - while much of western Ukraine wants closer ties with the 28-nation European Union, its eastern and southern regions like Crimea look to Russia for support.
Faced with the Russian threat, Ukraine's new government has moved to consolidate its authority, naming new regional governors in the pro-Russia east, enlisting the support of the country's wealthy businessmen and dismissing the head of the country's navy after he declared allegiance to the pro-Russian government in Crimea.
Looming over the political crisis is Ukraine's teetering economy, with a top economic official saying that it needs at least $35 billion to get through this year and next. Putin had promised a $15 billion loan in December, but Russia has only delivered $3 billion.
NATO held an emergency meeting in Brussels and the U.S., France and Britain debated the possibility of boycotting the next Group of Eight economic summit, to be held in June in Sochi, the host of Russia's successful Winter Olympics.
On Sunday evening, the White House issued a joint statement on behalf of the Group of Seven saying they are suspending participation in planning for the upcoming summit because Russia's advances in the Ukraine violate the "principles and values" on which the G-7 and G-8 operate.