In an interview with CNN television, Medvedev also confirmed that Prime Minister Binyamin Netanyahu made a secret visit to Moscow this month that included a meeting with the Russian president.
In a transcript of the interview released by the Kremlin on Sunday, Medvedev hedged on the question of whether Russia would support Iran if it were attacked by Israel.
Although Russia has no defense agreement with Iran "this does not mean we would like to be or will be indifferent to such an occurrence... But my Israeli colleagues told me they were not planning to act in this way, and I trust them," Medvedev said.
"When he visited me in Sochi, Israeli President Peres said something important for us all: 'Israel does not plan to launch any strikes on Iran, we are a peaceful country and we will not do this'," Medvedev said.
Medvedev also said the chances of an agreement with the United States on a new treaty to reduce strategic offensive weapons by the end of the year remain "quite high."
Israel has never officially made an open threat to attack Iran but has also insisted that it was not taking any option off the table regarding the Islamic Republic's contested nuclear program.
Iran insists its program is intended to produce energy.