Germany's government has repatriated eight women who allegedly left the country years ago to join Islamic State.
A charter flight with the German women and their 23 children landed shortly before midnight on Wednesday at Frankfurt airport.
They had been living in the Roj prison camp in north-eastern Syria, which is under Kurdish control.
Many of the returning women were detained upon landing, German Foreign Minister Heiko Maas said.
Another three women and their 14 children being brought back by Denmark were on board.
The US offered logistical support and Kurdish authorities helped prepare for the repatriation operation.
"The children are not to blame for their situation. It is the right thing for us to do everything we can to enable them to live safely and in a good environment," Maas said.
"The mothers will have to answer for their actions before the criminal justice system," he said.
Security sources said six of the women had arrest warrants issued against them, including three from Germany's federal public prosecutor.
Youth welfare authorities were checking where the children could be placed.
The repatriated children are classified as in particular need of protection and they are mainly ill or have guardians in Germany, Maas said.
German magazine Der Spiegel reported the women were aged 30 to 38 and some had been in detention centres with their children for years.
Germany has brought back women from Islamic State territory before, but this is the largest operation so far, according to tabloid newspaper Bild.
Several previous returnees have already stood trial in Germany on suspicion of terrorism and other charges.