Some countries use growth hormones to beef up their cattle
The European Union (EU) says it now has scientific evidence to support its ban on imports of beef raised using growth promoting hormones.
The ban is the subject of a long standing dispute with the United States, which currently has retaliatory sanctions on some imports from Europe.
A European Union spokeswoman says it can prove that growth promoting hormones used by cattle farmers in some countries can cause cancer and should therefore be banned.
She said the evidence is being shared with the US.
Washington made a complaint to the World Trade Organisation about the EU's hormone ban in 1996.
The complaint was upheld because the EU was said to have failed to justify its ban on the basis of adequate scientific evidence.
Europe refused to comply with the ruling, and the US has been applying punitive tariffs to some European goods, including French Roquefort cheese.
The EU says the new evidence means its ban is now consistent with WTO rules and the US sanctions should therefore be lifted.
This is one of a number of disputes that affect transatlantic trade relations.
The US has been found by the WTO to have tax breaks that are in effect banned subsidies for exporters.
The new tariffs on steel imports imposed by the US last year have also been ruled against, although Washington is currently appealing against that decision.