Russian President Vladimir Putin on Thursday hit out at the latest sanctions imposed by the U.S., calling Washington's move an “unfriendly act” that could backfire by spiking global oil prices.

New U.S. and European sanctions are part of a broadened effort to choke off the revenue and supplies that fuel Moscow’s fighting in Ukraine, compelling Putin to negotiate an end to the conflict.

Speaking to reporters in Moscow, Putin acknowledged that the “serious” U.S. sanctions would have “certain consequences” for Russia, but maintained that they would not significantly impact its economy.

Energy revenue is the linchpin of Russia’s economy, allowing Putin to pour money into the armed forces without worsening inflation and avoiding a currency collapse.

International crude prices jumped more than $2 per barrel Thursday on news of the new U.S. sanctions against Russia's oil giants Rosneft and Lukoil.

Putin said he warned U.S. President Donald Trump that an attempt to curb Russian oil exports would destabilize global oil markets and backfire against the United States.

He deplored the U.S. sanctions as an “unfriendly act” that would damage relations with Washington and said that Moscow wouldn't yield to pressure.

The U.S. sanctions came after Trump said that his plan for a swift meeting with Putin in Budapest was on hold because he didn’t want it to be a “waste of time.”

It was the latest twist in Trump’s hot-and-cold efforts to end the conflict as Putin refuses to budge from his demands.

Commenting on Trump's decision to put the planned summit on hold, Putin emphasized that it was the U.S. that proposed holding it and added that "dialogue is always better than confrontation.”

The Russian leader also warned that any attempt by Ukraine to strike deep inside Russia with longer-range weapons supplied by the West would mark an escalation.

It could trigger a “very serious, not to say stunning” response from Russia, he said.