Chancellor Angela Merkel on Thursday defended her government's program to improve the integration of Germany's immigrant population against criticism from leading Turkish groups that boycotted a key meeting on the issue. Three Turkish immigrant groups rejected Merkel's invitation to take part in Thursday's so-called "integration summit," saying planned changes to German immigration law are discriminatory. But Merkel heralded the summit, attended by some 90 participants, as "a milestone in integration policy" and insisted that in follow-up talks the government's "hand remains outstretched" to all groups - including those who took part in the boycott. Improved integration of Germany's estimated 15 million citizens and foreign nationals with an immigrant background has been a focus of Merkel's coalition government. She held the first "integration summit" last July and another, to check the progress on goals laid out Thursday, is planned for 2008.