Nikolai Patrushev, head of Russia's national security council, said Moscow had received no information from foreign intelligence agencies about Russian companies or individuals helping Iran build a nuclear weapon.
His comments came after Britain's Sunday Times, citing Russian and Israeli sources, reported that Israeli Prime Minister Benjamin Netanyahu had shown Russian leaders the evidence during a mysterious visit to Moscow last month.
"At the moment I do not know of any secret services or other agencies having given us information about our companies or individuals," Patrushev said, quoted by Interfax news agency, in response to the report.
"If they have such information, we will of course pay attention to it. But we do not have such information," added Patrushev, who is also a former chief of Russia's FSB security service.
Netanyahu's swift visit to Moscow on September 7, initially kept secret by Israeli and Russian officials, has been the subject of intense speculation.
The Sunday Times said that Netanyahu had presented a list of Russian atomic experts helping Iran with its nuclear programme during "a short, tense meeting" with Russian President Dmitry Medvedev and Prime Minister Vladimir Putin.
Israeli officials believe the Russian experts were working with the approval of the Russian government, the British newspaper said.
Tensions have mounted in recent months over Tehran's nuclear programme, especially with the revelation last month that Iran was building a previously undisclosed uranium enrichment facility near its holy city of Qom.
The United States, European Union and Israel fear that Iran may be seeking to build atomic weapons under the guise of a civilian nuclear power programme, but Tehran insists that the programme is peaceful in nature.
Russia is helping Iran build its first civilian nuclear power plant at the southern Iranian city of Bushehr, but Moscow says it is opposed to Tehran acquiring an atomic weapon.
