Such new targets of sanctions are announced every few weeks. But the announcements routinely come from the Treasury Department.
The Iran Times could not recall the White House ever before making such a routine sanctions announcement.
With Republicans attacking President Obama for not being tough enough on Iran, it may be that White House chose to make the announcement to try to rebut GOP attacks on his Iran policies.
The announcement quoted Obama saying, “If the Iranian government continues its defiance, there should be no doubt that the United States and our partners will continue to impose increasing consequences.”