The German government has weighed into the takeover row sparked by Sanofi-Synthelabo's hostile bid for French-German pharmaceutical group Aventis, describing the merger overture as very unusual.

The German economy ministry said it had been in contact with the French government on the bid, which according to Aventis could mean the loss of 10,000 to 12,000 jobs worldwide.

German Economy Minister Wolfgang Clement expressed Berlin's heightened interest in preserving German sites operated by Aventis, which was formed in 1999 from the merger of German group Hoechst and the French company Rhone-Poulenc and is today a larger operation than Sanofi.

Clement called Sanofi's offer for Aventis "a very unusual takeover bid" in comments to reporters on the sidelines of a meeting of his party in Berlin.

Aventis chairman Igor Landau, in a conference call with analysts said of Sanofi, a French company: "They need us but we don't need them." Sanofi, he added, "wants to buy what it does not have and take out an insurance policy" for its future.

He explained that one of Sanofi's principal products, the anti-thrombosis treatment Plavix, which faces legal difficulties in the United States, posed a risk for shareholders.

"Why should our shareholders take on the considerable risk associated with Plavix and other products without getting paid for it?" he asked.

Landau added that he would recommend that Aventis's supervisory board, which is scheduled to meet Wednesday, follow the lead of company directors and spurn the Sanofi bid.

Aventis predicts that 10,000 and 12,000 jobs worldwide could be lost if Sanofi-Synthelabo succeeds in the takeover, a source close to Aventis said Tuesday.

"The 1.6 billion euros in synergies envisaged by Sanofi-Synthelabo would come close to this figure, or 10 per cent of the workforces of the two groups," he said.

The warning echoed fears voiced by French trade unions after Sanofi launched a hostile stock-and-cash offer for Aventis that valued the group at about 47.8 billion euros (60.1 billion dollars).

But the bid has the blessing of the French government, which sees it as a formidable challenge to US and Asian competitors in the field of pharmaceutical research. If successful the takeover would create the world's third largest pharmaceutical group after Pfizer of the United States and GlaxoSmithKline of Britain.

French Finance Minister Francis Mer said: "We need actors that are as strong as possible in fields where research is fundamental."

In Germany, Roland Koch, the regional head of government in the state of Hesse, called on the federal government to intervene with the French government to halt the bid for Aventis, which employs 9,000 people in his state.

Koch said the takeover was "obviously a coordinated project (with) the French government," echoing suspicions that the French want to acquire a large part of Germany's biotechnology skills.

Sanofi meanwhile unleashed an advertising campaign aimed at wooing Aventis shareholders. The group purchased full-page ads in several newspapers, one of which depicted an ill child and said: "We reject the idea that we cannot quickly find a treatment that will cure Louis."

Combining the two group's research operations is a key reason for the Sanofi bid.

A defensive option for Aventis would be to find a third group prepared to make a better offer than Sanofi, with GlaxoSmithKline and Bristol Myers Squibb of the United States mentioned as possible candidates.

Another tactic would be a counter-bid, with Aventis launching its own hostile move on Sanofi, though most analysts discount this possibility.

On the Paris stock market shares in both groups gained ground, with analysts suggesting that Sanofi might be inclined to sweeten the deal.