A decision by the European Union to ban Iranian oil will have devastating effects for a struggling European economy, Iran\'s Foreign Ministry said. European foreign ministers agreed Monday to ban new oil contracts with Iran. Existing contracts are valid until July 1. The Iranian Foreign Ministry said the measure was \"imprudent and unjustifiable,\" Iran\'s state-funded broadcaster Press TV reports. The oil ban, the ministry added, would have adverse consequences for a struggling European economy. The Organization for Petroleum Exporting Countries said in its monthly report for January that the European economy was \"undoubtedly\" a global economic challenge. The cartel blamed volatile oil prices in 2011 partially on the European debt crisis, which OPEC said could \"seriously\" undermine growth expectations in the rest of the world in 2012. U.S. Secretary of State Hillary Clinton and Treasury Secretary Timothy Geithner, in a joint statement, said increased economic pressure on Iran was needed to curb its nuclear ambitions. \"Taken in combination with the many other sanctions on Iran that continue to be implemented by the United States and the international community, this new, concerted pressure will sharpen the choice for Iran\'s leaders and increase their cost of defiance of basic international obligations,\" they said. The European Union gets about 20 percent of its oil from Iran. Most of Iran\'s crude oil heads to markets in Asia.