The RIA news agency had reported Bogdanov's comments earlier on Wednesday, but when asked about it a spokeswoman for Staffan de Mistura, the UN special envoy, said in an email that talk about May 10 was speculation and that no date had been set.
De Mistura, who is struggling to keep negotiations alive after the main opposition High Negotiations Committee (HNC) left formal talks last week, was due to give a news briefing later on Wednesday, Reuters reported.
The Syrian government said on Tuesday it had held a final session of talks with de Mistura in a "useful and constructive round", but diplomats warned that an escalation of fighting around Aleppo threatened the shaky peace process.
George Sabra of the HNC said on Wednesday it was up to the United Nations to say when peace talks would resume, but said his group would not take part until its demands were met.
"All the while real steps aren't taken on the ground in Syria, the participation of the delegation of the HNC will remain suspended," Sabra told Reuters.