WASHINGTON (AFP) - The United States on Thursday imposed visa bans and set the stage for wider sanctions against Russia, warning any move to split the Crimean peninsula from Ukraine would break international law.
"In 2014, we are well beyond the days when borders can be redrawn over the heads of democratic leaders," President Barack Obama declared at the White House.
The stern message was aimed at President Vladimir Putin over Russia's incursion into Ukraine, and came as Secretary of State John Kerry worked in Europe for a diplomatic way out of the worst East-West crisis in decades.
The visa ban targets Russians and Ukrainians blamed for threatening the sovereignty or territorial integrity of Ukraine, where pro-Moscow president Viktor Yanukovych was ousted after mass protests last month.
They were also merely a first step. Mr Obama also signed an executive order paving the way for economic sanctions against individuals or entities in Russia.
The document sets broad criteria, and could target those accused or usurping peace and stability in Ukraine or Russian officials seeking to impose control over any part of the country.
"These decisions continue our efforts to impose a cost on Russia and those responsible for the situation in Crimea. And they also give us the flexibility to adjust our response going forward based on Russia's actions," said Mr Obama.
In practice, the sanctions may offer a way to crank up pressure on Mr Putin by restricting the assets or movement of senior figures around the Russian president. Those stripped of their visas would be informed, US officials said, refusing to make the list public.
But State Department spokeswoman Jen Psaki suggested Russian President Vladimir Putin was not on it. "Taking a step like that against a head of state is - would be a significant step, and it is not what we are leading with here in this process," she said.
US officials stressed however that, despite the deployment of Russian troops into southern Ukraine's Crimea peninsula, Washington had not seen any military moves into mainland eastern Ukraine.
In a bid to defuse the tensions on Europe's doorstep, Mr Kerry, who visited Kiev on Tuesday, held a second round of talks in two days with his Russian counterpart Sergei Lavrov.
But Mr Lavrov told Russian news agencies that so far "we cannot report to the international community that we are in agreement."
Angered by the show of Russian might, Washington has already pulled out of preparatory meetings for the G8 summit in Sochi and is working to put together a US$1 billion loan guarantee for Ukraine.
Other steps include suspending bilateral discussions on trade and investment.
While upping consequences for Russia over its move into Ukraine, Mr Obama also left open what US officials have been calling an off ramp for Putin.
He called for a diplomatic solution that would see Russian troops pulled back to barracks in Crimea, elections in Ukraine in May, international monitors to safeguard the rights of ethnic Russians in the region and retain Moscow's military basing rights on the peninsula.