The United States rejected the legitimacy of Crimea’s referendum to secede from Ukraine and join Russia in multiple statements Sunday.

According to exit polls, 93% of those who voted did so in favor of secession. Secretary of State John Kerry told Russia the US will not recognize Crimea’s referendum, and the White House again warned harsh sanctions will be passed.

Kerry called Russian Foreign Minister Sergei Lavrov and told him to pull forces back to the ports in Crimea and recognize the new Ukraine government in Kiev. Kerry wants Moscow to hold diplomatic talks with Kiev, but Moscow refuses. Russia has said many times it considers the new government illegitimate and headed by fascists.

Since Russia took control of Crimea, the US imposed visa bans and stopped trade talks and military exercises with Moscow. The US promised more sanctions if Russia recognizes the Crimean referendum and uses it to justify more aggression towards Ukraine:

“We are putting as much pressure on the Russians as we can to do the right thing,” White House senior adviser Dan Pfeiffer said as voters in Crimea, under the control of Russian forces, decided whether to break away from Ukraine and join Russia.

“You can expect sanctions designations in the coming days,” Pfeiffer told NBC’s Meet the Press, as the administration prepares to identify Russians whom the United States will seek to punish with visa bans and asset freezes the president authorized last week.

Pfeiffer said the sanctions will harm Russia’s economy and further isolate them from the rest of the world.

Meanwhile, US Press Secretary Jay Carney released a statement on the results of the poll:

The U.S. has steadfastly supported the independence, sovereignty, and territorial integrity of Ukraine since it declared its independence in 1991, and we reject the “referendum” that took place today in the Crimean region of Ukraine. This referendum is contrary to Ukraine’s constitution, and the international community will not recognize the results of a poll administered under threats of violence and intimidation from a Russian military intervention that violates international law.