NATO Secretary General Anders Fogh Rasmussen hit back at Russian claims that he was "blind" for not seeing evidence that Moscow was withdrawing its troops from Ukraine's border as Moscow has claimed.
"For those with a blind eye we suggest to follow President Putin's statement of May 7," Russia's Foreign Ministry said earlier.
On Wednesday, President Vladimir Putin said that Moscow had withdrawn troops from the border. American officials also say the see no evidence of a Russian withdrawal.
Also on Thursday, pro-Russian separatists in two Ukrainian cities vowed to continue with a referendum on autonomy planned for Sunday despite Putin's call to delay the vote.
Reuters contributed to this report.