An American veterinary delegation has decided to extend its stay in Moscow, hoping convince Russia to lift a ban on U.S. chicken imports. The ban was imposed officially due to health concerns, but some say larger trade issues are at the root of the problem.

The U.S. officials have already been in Moscow for the past week but say they need more time to deal with the sensitive issue over imported chicken. Russia imposed a total ban on American poultry products after health inspectors reported finding salmonella bacteria in various samples of chicken.

Russian officials have also expressed concern about the use of antibiotics on U.S. farms that produce the chickens. The Russians say they want a new agreement to regulate such practices. The U.S. delegation has stressed that American poultry is safe and that concerns about health problems are exaggerated.

The Moscow ban represents a serious threat to U.S. poultry and feed-meal producers, because around half of all American poultry exports go to Russia.

U.S. chicken has much more meat than Russian poultry, which tends to be lean and scrawny. The American chicken is also much cheaper than the local variety. Russian critics say the U.S. chicken is fatter and less healthy because the birds receive large doses of antibiotics to fatten them up.

The dispute over chicken began before President George W. Bush's recent decision to raise tariffs on imported steel by as much as 30 percent. That move is likely to have an impact on Russian exports of steel.

Despite headlines about a "chicken vs. steel" trade war, officials on both sides have said there is no linkage between the two products.