"I am very encouraged to see an apparent willingness by the US to look seriously at farm reform and put the US Farm Bill on the table," said EU agriculture commissioner Mariann Fischer Boel.

"We in Europe have just put in place the biggest ever reform of the Common Agricultural Policy. We are prepared to bind that reform contractually into a deal in the World Trade Organisation, but our partners must match our ambition," she said in a statement.

"So I hope the US will follow our good example. Farm subsidy reform is vital to boost world trade and to help the developing world out of the cycle of poverty," she added.

When asked in an interview by Britain's ITV television whether the United States would drop its subsidy system, Bush replied: "Absolutely. And I think we have an obligation to work together to do that."

"We've got agricultural subsidies, not nearly to the extent that our friends in the EU have," he noted.

But Fischer Boel noted that the amount paid in subsidies to European farmers is no longer linked to how much they produce.

"US payments, by contrast, are still largely production-linked and therefore seriously distort trade," she said.