BERLIN: Disagreements over intellectual property rights mean Germany, France and Spain have yet to agree the next steps for a joint fighter jet project, the defence ministry in Berlin said on Saturday after a deadline to find a solution ran out.

Last week, the defence ministers of Germany and France set an end-April deadline to broker a deal over the Future Combat Air System (FCAS), Europe's largest defence project.

"No agreement over the use of the intellectual property rights has been found yet," a ministry spokeswoman said. "For Germany, unrestricted access to the results of the jointly financed research is of utmost importance."

The countries were aiming for an agreement next week, she added.

Costing more than 100 billion euros ($120 billion), the development of the jet brings together Germany, France and Spain.

Dassault Aviation, Airbus and Indra are involved in the scheme to start replacing France's Rafale and German and Spanish Eurofighters from 2040.

Berlin's defence ministry spokeswoman said there needed to be an adequate arrangement for the use of intellectual property rights in the jet which respected the interests of all participants in the project.

She said negotiations were continuing and it remained Germany's goal to present a proposal to the parliament's budget committee in June.

The next step of the jet's development is conditional on the German parliament's approval, and time is running out to find a solution to present a proposal in time for the parliament's budget committee to vote upon it before a general election in September.

Previously, a source with knowledge of the issue had told Reuters that the German defence ministry has to refer the budget proposal to the finance ministry by May 19.

Earlier this week, MTU Aero, Safran and ITP Aero solved their row about the development and production of the jet's engines, agreeing to share the workload evenly between the three companies.