At an international Middle East conference in Jordan, Yevgeny Primakov said any such move would only serve to further radicalize the Iranians, RIA Novosti reported.
"In that situation, Iran could consider it absolutely vital to have nuclear weapons," he said. "Iran has attained the level of a Middle East power that must be reckoned with."
Iran has announced any attack on its nuclear facilities would be considered a declaration of war. It threatens to launch missiles at Israel in such an event and to close the Straight of Hormuz, a strategic narrow passage used by oil tankers leaving the Persian Gulf.
Iran has repeatedly denied allegations by the West that it is using its nuclear program to secretly develop atomic weapons.