Speaking on CHQR radio in Calgary, Alberta, the Conservative leader said Tehran's recent disclosure it was processing its own uranium to weapons-grade capability, firing cruise missiles in the Strait of Hormuz and warning the United States to keep aircraft carriers away showed a worsening situation.
"Iran is a very serious threat to international peace and security. In my judgment, it is the world's most serious threat to international peace and security," Harper said Thursday.
"This is a regime that wants to acquire nuclear weapons, it is clearly trying to acquire nuclear weapons, and it has indicated some desire to actually use nuclear weapons."
Harper said "even the Chinese and Russians" were aware of the mounting threat but the international community's various sanctions against Iran so far weren't enough to deter the Iranian regime, Postmedia News reported.
"I think the problem is there's not [international] consensus on what to do about it precisely," Harper said.