By David Brunnstrom BRUSSELS, March 1 (Reuters) - An aide to European Union foreign policy chief Javier Solana said on Thursday there were limits to how far some EU states would go in tightening sanctions on Iran over its nuclear programme. Annalisa Giannella, Solana's personal representative on non-proliferation and weapons of mass destruction, told a European Parliament committee EU sanctions were already tougher than those agreed by the United Nations Security Council. She said EU member states would implement them faithfully and tighten them if Tehran refused to halt a uranium enrichment programme the West says is aimed at producing an atomic bomb. "But you can't, I think, expect member states even to cancel contracts that are in areas that have nothing to do with proliferation or the nuclear or ballistic, etc," she said. "There are some countries in the EU who in terms of trade have strong economic interests and it is impossible from one day to another just to drop all this, because that would imply very negative consequences for our economies as well." The U.N. sanctions adopted in December bar the transfer of technology and know-how to Iran's nuclear and missile programme. Major world powers have been in talks over stiffer sanctions after Tehran ignored a Feb. 21 deadline to stop enriching uranium, a programme it says is entirely peaceful. Washington is leaning on its European allies to ban investment and export credits for Iran. EU leaders have resisted due to a lack of legal mechanisms, hefty stakes in what they see as legitimate business with Iran, and some misgivings about a U.S. policy to rapidly isolate rather than negotiate with Tehran, a major oil exporter. Giannella said an EU working group would discuss this month the possibility of adding individuals or entities to the sanctions list. But she added: "There is jurisprudence of the (European) Court of Justice which says we have to have serious grounds for each and every person that is affected by a sanction so we have to be very careful and 100 percent sure that the addition is justified." Giannella said she believed Washington was committed to seeking a negotiated solution to the crisis, despite its military buildup in the Gulf. "Probably they think that it is better to show their muscles. Probably they think that in addition to the pressure by the Security Council it is good also to show their military capabilities," she said.
