Merkel was speaking at a press conference following a meeting with ethnic leaders in Berlin to announce government assistance to minorities which are widely seen as becoming increasingly detached from the mainstream German society.

The 90 community leaders at the summit adopted a "national integration plan" containing 400 promises for improvements -- ranging from aid for ethnic sports clubs to making more German-language classes available -- which Merkel said was the first in Germany's post-Second World War history.

The summit, however, was held under a cloud after four major Turkish groups boycotted the event in protest at legislation passed last week which raises the hurdles for newly wed Turkish citizens moving to Germany to live with their spouses.

Discriminatory law?

Under the new law, husbands or wives of immigrants living in Germany can only obtain permanent residency in the country if they are aged 18 or over and can speak between 200 and 300 words of German. The law is widely seen as an attempt at stamping out the practice of forced marriages on German soil.

Merkel rebuked the Turkish groups which boycotted the summit and denied claims that the legislation treated Muslims differently from anyone else. She said the law had implemented an EU guideline and included a wide range of exemptions.

"One does not issue the federal government with ultimatums over legislation that has been approved by parliament," the conservative chancellor told reporters at the end of the one-day conference. "But we continue to hold out our hand, all they have to do is accept the next invitation when it comes up."

The chancellor said that the next integration summit would be held in autumn 2008 to assess progress.

"We have a lot to do," Merkel said. "We invite everyone to get involved once again."

Heated debate

Kenan Kolat, chairman of a secular association, Turkish Community -- which rejected the invitation to attend the Berlin summit along with the Ditib network of mosques, the Turkish Parents' Association and the Council of Germans of Turkish Extraction -- said in a television interview that his group would challenge the legislation as discriminatory in Germany's constitutional court after it had been gazetted into law.

"The Turkish community is not taken seriously," Kolat said. "We are treated like children who understand nothing of the law."

He added that the new legislation did not apply across the board but sought to turn some immigrants into "second-class citizens."

Citizens of EU member states and other countries that do not need a visa to travel to Germany, including Australia, Israel, Japan and the United States, have been exempted from the new immigration regulation.

Bekir Alboga, the leader of Ditib, said he was happy to talk about integration but had boycotted the Berlin meeting in protest at the immigration act.

"We have nothing against pursuing a dialogue but we are very much against the immigration law," Alboga told the press. "It has made second-class citizens of many foreigners."

"Somebody called Hans can bring his wife from Turkey or India into the country without a problem, but if your name is Ali and you have Turkish roots, then this becomes a lot harder," he said.

New education and sponsorship measures agreed

Earlier on Wednesday, the German government approved a package of 150 measures to bring immigrant communities into mainstream German society, including an expansion of cut-price German-language courses.

The length of time that each immigrant can attend such a course was increased by 50 percent.

Private language schools and non-profits, which obtain federal grants to conduct the courses, must also provide baby-sitting services for mothers while they learn German and there will be extra grants to train the illiterate and difficult-to-educate teenagers.

Maria Böhmer, federal migration commissioner, said such classes had been a big success so far, with two thirds of the students being women.

The federal government also aims to set up a network of sponsors to help immigrant families.

Germany has a population of nearly 82 million, of whom 7.3 million are not German citizens, according to official statistics.

But the federal government estimates that ethnic minorities total 15 million people, including those who have obtained German citizenship by naturalization or because they were children of mixed marriages between a German and a foreigner.

Minorities in public service

Amid fears that poor minorities may be radicalized, business leaders also attended the "integration summit." They have been pressed to train and employ larger numbers of immigrant youths.

Brigitte Zypries, Germany's justice minister, said a survey showed there were far too few minority trainees in public services.

"A survey in 2005 of trainees in the public services found only 2.1 percent were foreign young people compared with 24 percent in job training overall," she said. The public services "clearly" told the summit they would try to improve this.

The cabinet also set a target of creating an additional 10,000 jobs for people of foreign origin by 2010.