The US sanctions on Iran are unilateral.
http://www.parstimes.com/law/ilsa96_factsheet.html
http://www.dbtrade.com/publications/182447w.pdf
http://www.treas.gov/offices/enforcement/ofac/sanctions/t11iran.pdf
The US is pressing the UN for international sanctions.
Many Thanks for the responses, especially for the links Dr. Z.
Prairie