REUTERS/Thomas Peter
Armed men, believed to be Russian soldiers, stand guard outside a Ukrainian military base in Simferopol March 19, 2014. Defying Ukrainian protests and Western sanctions, Russian President Vladimir Putin signed a treaty in Moscow on Tuesday making Crimea part of Russia again, but said he did not plan to seize any other regions of Ukraine.
"The question at this point is not if we will do more sanctions, it's when," State Department spokeswoman Jen Psaki told reporters.
On Monday, Washington rolled out a series of sanctions against 11 mostly Russian officials, including seven of President Vladimir Putin's inner circle.
Psaki insisted there has been "a huge economic impact" following Moscow's intervention in Crimea.
Asked about reports that the whole 450-member Russian Duma has responded by calling on the US to sanction them, Psaki retorted: "Be careful what you ask for."
Publicly, Russian officials have laughed off the US sanctions, which freeze their assets in the US, despite similar travel bans and sanctions imposed by the EU.
But Psaki hit back "that there is real economic pain, and if President Putin cares about the economy in his country, cares about the economic impact on the people of his country, cares about his place in the world, then those are all factors that should be looked at."
She reeled off a list of figures, including that Russian stock indexes plunged 17 percent Friday to their lowest levels since 2009, and that the ruble has hit a five-year low against the dollar.
"Russia's 19 richest people lost $18.3 billion due to stock market volatility on March 3 -- the first day of trading after the beginning of Russian military intervention in Crimea," Psaki told reporters.
"More capital has already fled Russia this year than in all of 2013. And finally, forecasts for Russia's 2014 growth rate hover around under one percent. Some even predict a negative growth rate."
It remains unclear when more US sanctions could follow, but President Barack Obama has called for the EU and the G7 group of most industrialized nations to meet on Ukraine next week in The Hague.
Britain announced Tuesday that it had suspended all military cooperation with Russia and halted export licences for military material.
And Germany halted a major deal to provide a fully equipped training camp to Russian forces reportedly worth about $140 million.
US officials hope that they can force Putin's hand by keeping up the threat of even more sanctions.
"I wouldn't, if I were you, invest in Russian equities right now -- unless you are going short," White House spokesman Jay Carney said earlier this week.
