Airbus nations urged the European Union to appeal against a global trade ruling condemning loan payments to the planemaker and pledged to continue discussing financing for the A350 jet.

The ruling from the World Trade Organization failed to establish that Europe's system of aircraft loan financing as a whole was at fault, European officials said.

Ministers from France, Germany, Britain and Spain -- four countries that founded Airbus 40 years ago -- discussed the issue on the sidelines of the Farnborough Airshow. "It is an unfair situation. All four of us deplore it and our wish is that the (European) Commission appeals as quickly as possible," French Transport Minister Dominique Bussereau said.

"France believes the WTO panel confirmed that the principles of reimbursable advances do not contravene WTO rules," he told a news conference.

Airbus is in talks with European governments to obtain further loans for development of its future A350 jet, to be paid back from a royalty on future sales of the plane.

"I can say we are encouraged by progress to date," Mark Prisk, junior British minister for business, said of the talks.

"Clearly it's a complex set of negotiations and obviously all of us are committed to acting consistently with our international obligations, as you would expect."

Ministers said France was in discussions to supply EUR€1.4 billion, Germany EUR€1.12 billion, Spain EUR€332 million and Britain GBP£340 million in A350 development loans.

Boeing says such loans are unfair and should be withdrawn. It reiterated calls for future loans to be on a commercial footing.

"The WTO has set a clear legal principle that government loans to Airbus must be on commercial terms, otherwise they are an illegal subsidy and inconsistent with WTO rules," Boeing spokesman Charlie Miller said.

The WTO said last month three European countries had given prohibited export subsidies as loans for the A380 superjumbo.

Prisk said the four countries were unhappy about a WTO decision to delay ruling on an EU counter-case which alleges that Boeing received illegal aid in research grants.

The EU has until July 21 to appeal in the original case brought by the United States and is expected to do so -- a move that legal experts say would trigger a US counter-appeal.