(CNN) -- The United States and European Union announced sanctions including asset freezes and travel bans on officials from Russia and Ukraine after Crimea applied to join Russia on Monday following a controversial weekend referendum.
"We'll continue to make clear to Russia that further provocations will achieve nothing except to further isolate Russia and diminish its place in the world," President Barack Obama said. "The international community will continue to stand together to oppose any violations of Ukrainian sovereignty and territorial integrity, and continued Russia military intervention in Ukraine will only deepen Russia's diplomatic isolation and exact a greater toll on the Russia economy."
The sanctions came after Crimea's Moscow-backed leaders declared an overwhelming 96.7% vote in favor of leaving Ukraine and being annexed by Russia in a vote that Western powers said was illegal. Turnout was 83%.
The result did not come as a surprise. But what happens next is far from certain. Diplomatically, Sunday's referendum has put the United States and Russia on the kind of collision course not seen since the Cold War. Economically, it's unclear how much such a coupling will cost Russia. And politically, it's divided Crimeans, some of whom think it will bring better pay and some who see this as a Kremlin land grab.
After a meeting in Brussels, the EU's 28 foreign ministers agreed on a list of those to be sanctioned for their part in the seizure of Crimea by pro-Russian forces and the referendum.
"(Foreign Affairs Council) just agreed on sanctions -- travel restrictions & assets freeze against 21 official from Ukraine & Russia," Lithuanian Foreign Affairs Minister Linas Linkevicius wrote in a message on Twitter.
He said more measures would follow in a few days, when EU leaders meet for a summit in Brussels.
German Foreign Minister Frank-Walter Steinmeier said those targeted included eight top Crimean officials and 10 people from Russia, including members of Parliament, as well as three military personnel.
Washington said it had targeted Russian officials and lawmakers, as well as Crimea-based separatist leaders, with financial sanctions for undermining "democratic processes and institutions in Ukraine."
President Barack Obama's order freezes any assets in the United States and bans travel for the 11 people named. Among those sanctioned were ousted Ukrainian President Viktor Yanukovych and aides to Russian President Vladimir Putin.
Earlier, lawmakers in Crimea approved a resolution that declared the Black Sea peninsula an independent, sovereign state. They then filed an appeal to join the Russian Federation.
Moscow strongly backed Sunday's referendum; the majority of the population is ethnic Russian. And Russian lawmakers have said they will welcome Crimea with open arms.