Obama warns firms of violating sanctions on Iran

Companies that explore business opportunities in Iran do so "at their own peril", US President Barack Obama said Tuesday, vowing that the US will come down "like a ton of bricks" on sanctions violators.

The president made the remarks at a joint news conference with his French counterpart, Francois Hollande, alluding to a trip to Iran by a large French trade delegation earlier this month, Xinhua reported.

"President Hollande and I agree on the need to continue enforcing existing sanctions even as we believe that new sanctions during these negotiations would endanger the possibility of a diplomatic solution," Obama said.

"Businesses may be exploring -- are there some possibilities to get in sooner rather than later if and when there is an actual agreement to be had?" Obama said. "But I can tell you that they do so at their own peril right now, because we will come down on them like a ton of bricks."

World powers sealed a landmark preliminary deal with Iran in November, under which Tehran agreed to halt its most sensitive nuclear operations in return for winning some relief from sanctions.

The US and the European Union have suspended some sanctions on Iran under the interim deal.

Washington, however, has warned that the interim nuclear deal does not mean Iran is "open for business" and vowed to vigorously enforce existing sanctions.