JOIN USHe made the statement in the wake of the recent revelation of an alleged plot to assassinate Saudi ambassador to Washington.
"What "we're going to continue to do is to apply the toughest sanctions and continue to mobilise the international community to make sure that Iran is further and further isolated and pays a price for this kind of behaviour," said Obama during a joint press conference with visiting South Korean President Lee Myung-bak.
"This is not just a dangerous escalation," said Obama, "This is part of a pattern of dangerous and reckless behaviour by the Iranian government."
He said Iran's involvement in the plot indicates "the degree to which it has been outside of accepted norms of international behaviour for far too long."
"This is just one example of a series of steps that they've taken to create violence and to behave in a way that you don't see other countries doing," Obama added.
Two men --Manssor Arbabsiar, a 56-year-old naturalised US citizen holding both Iranian and US passports, and Iranian Gholam Shakuri -- have been charged by the US Justice Department Tuesday for their alleged participation in the plot to assassinate the Saudi ambassador to the US.
The US alleged that the plot was directed by senior members of the Quds Force, an elite division of Iran's Revolutionary Guard Corps responsible for foreign operations.