Leading members of Germany's Social Democratic Party (SPD) have voiced opposition to Nato's campaign. They are attending a special party conference where Mr Schröder will be formally elected the party's chairman.

But Mr Schröder argued that Germany had a special responsibility to stand firm against Yugoslav President Slobodan Milosevic because of the nation's Nazi past.

Terry Stiastry in Berlin: "Left-wingers have called for an immediate cease fire2

"Our response must be clear," said Mr Schröder. "We must never again allow murder, expulsions and deportations to be tolerated by politicians."

The Nato attacks mark the first time that Germany's military has been drawn into combat against a sovereign country since World War II.

German Tornado jets are helping to attack Serb air defence radar systems and protect Nato bombers which have destroyed many military and strategic targets.

Germany provides a base for the US as well as having its own military involved

Mr Schröder told the 470 conference delegates in Bonn that Germany's credibility as a Nato ally was at stake.

"We have a responsibility toward our allies in Nato," Mr Schröder said.

"We also have a responsibility toward the people of Kosovo who have become victims of the most gruesome human rights violations."

Strong objections

The chancellor's stand has provoked vocal objections from a minority in the party as well as the once thoroughly pacifist Greens, Mr Schröder's junior coalition partner.

Protestors block the US air base in Spangdahlem western Germany

Left-wingers and the Social Democrats' radical youth organisation introduced a motion at the convention calling on the government to press for an end to the air strikes and for fresh Kosovo peace talks with Yugoslavia.

A victory for the anti-war faction could have serious consequences for Nato's so far united front.

But the BBC's European Affairs correspondent William Horsley reports that outcome is unlikely as the anti-war movement in Germany has been more subdued than in some other member states of the alliance.

However there is considerable public unease that the policy is causing enormous damage to the Serbian economic infrastructure without as yet achieving its goal of rescuing Kosovo-Albanians persecuted by Serb forces.

New appointment

The Kosovo crisis overshadowed a meeting originally called to install Mr Schröder as new party chairman.

The post fell vacant after the dramatic resignation last month of Oskar Lafontaine the party chairman and and finance minister.