Obama: New Sanctions Against Russia Will Have 'An Even Bigger Bite' President Obama promised that "the cost on Russia will continue to grow."

 -- The United States will unleash a new round of sanctions against Russia in the wake of the downing of Malaysia Airlines Flight 17, President Obama said today.

“The cost on Russia will continue to grow,” the president said in a statement at the White House emphasizing Russian "energy, arms and finance" as targets. “Today is a reminder that the United States means what it says.”

Obama said Russia has, so far, “failed to cooperate with the investigations” into the downing of the Malaysian aircraft, adding that he and key European leaders "are united in our view that the situation in Ukraine ought to be resolved diplomatically."

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Obama said he has been coordinating closely with European allies to ensure a unified response. Earlier today, the European Union agreed to a new package of sanctions on Russia, for the first time imposing “sectoral” sanctions on Russia’s finance and energy industries, as well as banning arms exports to Russia.

Obama, in his remarks this afternoon, called them the “most significant and wide-ranging sanctions to date.”

The European Union says the sanctions will limit access to E.U. capital markets for Russian state-owned financial institutions, impose an embargo on trade in arms, establish an export ban for dual-use goods for military end-users, and curtail Russian access to sensitive technologies, particularly in the oil sector.

Meanwhile, at the State Department, spokeswoman Jen Psaki emphasized that the United States welcomed “Europe’s determination to take strong new steps and ... this trans-Atlantic community and G-7 are united in their determination to respond to continued and intensified Russian aggression.”

ABC News' Jon Williams and Ali Weinberg contributed reporting.