He was reacting to Polish Foreign Minister Radosław Sikorski's words about a possible scenario on the part of the United States in response to Putin's use of nuclear weapons.
Medvedev said, "First, the Yanks have not said anything like that so far, because they are more cautious than the Poles. Second, an American strike on our targets means the beginning of a world war, and the foreign minister of even a country like Poland should realize this."
He also mentioned Warsaw's desire to host U.S. nuclear weapons on its territory as part of NATO's Nuclear Sharing program. He said that given this factor, if a world war breaks out, Poland "will not be left behind and will surely get its share of radioactive ashes."
The day before, Radosław Sikorski said that the US had warned Putin about the consequences of using nuclear weapons in Ukraine. He quoted the Americans as saying, "If you detonate a nuclear bomb, even if no one dies, we will strike your positions in Ukraine with conventional weapons, we will destroy them all."
The minister also recalled that China and India had earlier warned Russia against using nuclear weapons. Sikorski emphasized: "This is not child's play. If the taboo is broken, like the ban on forceful border changes, China knows that several countries, including Japan and South Korea, will become nuclear powers at once."