US President Barack Obama imposed sweeping sanctions Friday on Russia-annexed Crimea with an executive order prohibiting American exports of goods or services to the contested peninsula and barring Crimean imports.
US neighbor Canada also slapped new sanctions on Russia, hitting the country's oil and gas sector and targeting 20 Russian politicians as well as Ukrainian separatist leaders.
Obama said his executive order "is intended to provide clarity to US corporations doing business in the region and reaffirm that the United States will not accept Russia's occupation and attempted annexation of Crimea."
The action bans new US investments in Crimea and authorizes the US Treasury to impose sanctions on people and companies operating there. It also forbids trade of technology or services between Crimea and the United States.
"I again call on Russia to end its occupation and attempted annexation of Crimea, cease its support to separatists in eastern Ukraine, and fulfill its commitments under the Minsk agreements," Obama said.
The Minsk Protocol signed in September led to a ceasefire in eastern Ukraine but failed to stop the fighting.
Obama's order came a day after he signed into law a congressional bill allowing him to impose new sanctions on Russia over its alleged support of pro-Russian separatists in eastern Ukraine.
That law also authorizes the president to send lethal weapons to Ukraine's military.
But Obama stressed he would not change his administration's "carefully calibrated" sanctions policy on Russia.
Russian forces invaded Ukraine's Crimea region in March after a Ukrainian revolution ousted Kiev's pro-Kremlin president. Crimea residents voted in a disputed referendum to join Russia.
- International effort -
The multi-pronged sanctions effort is the latest punitive action against Russia, which was hit Thursday by a European Union decision to impose sanctions on Crimea.
The move was announced during an EU leaders summit where the bloc urged Russian President Vladimir Putin to make a "radical change" in his stance on Ukraine.
The EU agreed to ban all investment in Crimea and cruise ships from its ports.
Obama said he "will continue to review and calibrate our sanctions, in close coordination with our international partners, to respond to Russia's actions."
Western powers have repeatedly accused Russia of stoking the Ukraine crisis, which has killed at least 4,700 people and displaced nearly one million, by supplying weapons and troops to the rebels.
Moscow denies the charge.
In announcing his country's sanctions, Canadian Prime Minister Stephen Harper warned that "the Putin regime has continuously violated the territorial integrity, sovereignty and independence of Ukraine."
"Canada will not accept the illegal occupation of Crimea and persistent, provocative military activity in eastern Ukraine," he added.
While Putin has shown no willingness to change tack, even as Russia's economy comes under increasing pressure from a plunging ruble, Canada's Foreign Minister John Baird insisted the West's stiffening sanctions are working.
"There is no doubt that collectively the sanctions have been effective," Baird said.
Canada's travel bans impact mostly members of the Russian State Duma and ministers of the self-declared Donetsk People's Republic in eastern Ukraine.