BERLIN (AP) — German authorities have arrested four Iraqis suspected of membership in the Islamic State group, including one who is alleged to have carried out attacks that killed and wounded U.S. troops, officials said Thursday.

The men were arrested Wednesday in the western cities of Dortmund and Bottrop, and Amberg-Sulzbach county in Bavaria, the federal prosecutors’ office said in a statement.

Among those arrested was Mohammed Rafea Yaseen Y., who is suspected of joining the Islamic State of Iraq group in his western hometown of Rutba in 2006. The 27-year-old Iraqi, whose surname wasn’t provided due to German privacy rules, allegedly helped make improvised explosive devices and used them to carry out 12 attacks around Rutba between 2006 and 2008, prosecutors said.

U.S. troops were killed or wounded in the first 10 attacks, while Iraqi security forces and civilians were killed in the other two, according to the prosecutors’ statement.

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Markus Schmitt, a spokesman for the prosecutors’ office, was unable immediately to provide details of the attacks. But he said Y., who was under 18 at the time of the bombings, would be tried as a minor for those attacks if the case goes to trial.

The Islamic State of Iraq, also known as al-Qaida in Iraq, changed its name to Islamic State of Iraq and the Levant in 2013 and became known under the acronym ISIS, or just IS.

After that time Y. is accused of serving as an IS guard, including during two mass executions of men, women and children.

Another suspect, named only as 26-year-old Iraqi Hasan Sabbar Khazaal K., is accused of producing and distributing propaganda material for IS. This included filming executions, punishments and military operations by IS. Residents of Rutba were forced to watch the footage, federal prosecutors said.

Two other Iraqis, identified as 29-year-old Jamer Amer Jawad A.-A. and 28-year-old Muqatil Ahmed Osman A., are accused of taking part in military training with IS. The younger man is suspected of taking part in combat and performing guard duty.

All four left Iraq in mid-2015 and entered Germany soon after, prosecutors said.