The Russian Foreign Ministry said it had noted a sharp intensification of provocations targeting Russian diplomats in the United States.
"In recent days, following the announcement of the removal from [the US] of 60 Russian diplomats, US intelligence agencies have been making feverish attempts to contact them," the ministry said in a statement on its website.
The ministry also noted that "there was a series of outrageous episodes" when diplomats whom Washington had pressed to end their business trips, were offered "assistance" in exchange for unofficial relations "on a mutually beneficial basis."
The statement also noted that the Russian diplomats are "literally attacked" by the intelligence agencies' proposals.
The US expelled 60 Russian diplomats and closed the Russian Consulate General in Seattle in solidarity with the United Kingdom that had expelled 23 diplomats earlier. Another 25 countries have also made similar moves.
Russia has strongly rejected the accusations of the involvement in the poisoning as groundless and offered assistance in the ongoing probe; however, Moscow’s requests for samples of the chemical substance allegedly used to poison the ex-spy have been rejected.