Washington (AFP) - Russia has canceled a meeting with senior US diplomats in the wake of Washington's decision to reinforce sanctions imposed over its interference in Ukraine and occupation of Crimea.
US Under Secretary of State Tom Shannon had been due in St Petersburg on Friday to mend diplomatic fences with Russia's Deputy Foreign Minister Sergei Ryabkov.
But relations between Moscow and Washington are at a low even by the standards of a rivalry that goes back to the Cold War, and Washington's decision to ramp up its sanctions regime provoked the anger of President Vladimir Putin's Kremlin.
Shannon had hoped to address "irritants" in the relationship, such as tension over Moscow's intimidation of US diplomats and the US seizure of two Russian diplomatic compounds near Washington and New York.
But even this minor first step towards finding enough common ground to allow the rival nuclear powers to begin to address more fundamental issues -- such as Russia's intervention in Ukraine -- has now fallen apart.
"We regret that Russia has decided to turn away from an opportunity to discuss bilateral obstacles that hinder US-Russia relations," spokeswoman Heather Nauert said.
On Tuesday, the United States added 38 individuals and entities to its sanctions list targeting the Russians and pro-Russian rebels it blames for the fighting in Ukraine.
This appears to have been what triggered Moscow's decision to cancel the meeting, although US President Donald Trump also met Ukraine's President Petro Poroshenko on Tuesday.
But the State Department insisted that the sanctions were not being expanded, merely "maintained," by adding new targets as Moscow finds ways around the previous embargo.
And Washington insisted the punitive measures would stay in place until Russia honors the Minsk agreement to disengage from eastern Ukraine and returns the annexed Crimea region to Kiev.
"We have regularly updated these sanctions twice a year since they were first imposed," Nauert explained. "Let's remember that these sanctions didn't just come out of nowhere.
"Our targeted sanctions were imposed in response to Russia's ongoing violation of the sovereignty and territorial integrity of its neighbor, Ukraine," she said.
- 'Not the moment' -
Russia's foreign ministry said that, given the new sanctions, it was "not the moment" to hold the Shannon-Ryabkov talks, which Washington had announced on Tuesday.
And, asked whether the meeting could be rescheduled, spokeswoman Maria Zakharova said: "I have no confirmation that these consultations will take place."
Separately, Ryabkov himself, in a foreign ministry statement, threatened that Moscow would take retaliatory measures.
"This measure will not remain without a reaction -- there will be measures in response on our behalf," he warned.
"We regret that once again the American authorities have allowed themselves to be guided by the frenzied Russophobes in Congress, who will stop at nothing to cause us trouble, and especially to reduce to zero any chance of an improvement in Russian-American ties," he alleged.
- Putin's 'best friend'? -
Ryabkov's reference to Congress reflects a view in Moscow that Trump's arrival in the White House might have heralded a new friendship with Putin's Kremlin were it not for domestic US opposition.
Trump had warm words for Russia during his election campaign -- and earlier, such as when he promoted the Miss Universe beauty pageant in Moscow in 2013 and tweeted that he would like to become Putin's "best friend."
But since coming to office, Trump has become embroiled in intrigue surrounding the alleged attempt by Moscow's agents to swing the election in his favor by hacking the emails of his opponents and spreading online propaganda.
Trump has also appointed more orthodox national security officials, such as Secretary of State Rex Tillerson and Defense Secretary Jim Mattis, who remain wary of Moscow and see Russia as a strategic opponent.