Nations that have ordered Airbus' A400M military transport plane met Tuesday with parent company EADS before a weekend deadline to find a solution to the troubled project, an official said.

The negotiations in Berlin were the third round of talks in as many weeks. The manufacturer wants a decision by the end of the month.

EADS is urging the seven customer nations — Belgium, Britain, France, Germany, Luxembourg, Spain and Turkey — to increase their funding for the aircraft's construction, which is now four years behind schedule and more than euro5 billion ($7.08 billion) over budget.

The meeting at the German Defense Ministry lasted for five hours but ended in the evening with no conclusion, a ministry spokesman said on condition of anonymity in line with department policy.

He said the two sides had agreed to continue the talks soon, but said no details on location or timing had yet been worked out.

He gave no further details of the meetings, and an EADS spokesman also declined comment.

The industry delegation was led by EADS CEO Louis Gallois and the chief of its plane-making subsidiary, Airbus, Tom Enders, a source close to the negotiations told the AP on condition of anonymity due to the sensitivity of the talks.

Germany's Defense Ministry declined to comment on a report Tuesday in the Financial Times Deutschland that Germany was offering a loan guarantee to EADS instead of fresh money. The report cited unidentified sources close to the negotiations.

German Defense Minister Karl-Theodor zu Guttenberg has said his country "wants the A400M, but not at any price."

The defense officials and the industry are trying to reach a compromise on Airbus' claim that it can't afford to produce 180 planes under the original, fixed-price contract from 2003.

EADS has given the customer governments until the end of January to decide upon the funding. It is far from clear whether such a deadline can be met.

The A400M had its maiden flight last month. The four-engine turboprop is seen as inhabiting an important niche market between the Lockheed Martin C-130J Hercules, which carries only half the payload, and Boeing's C-17 Globemaster III, which is larger, costlier, and less tactically versatile.