ANKARA, Turkey (AP) — Turkish authorities have arrested two more people with suspected links to the suicide bomber who killed 10 Germans in Istanbul last week, raising the number of arrests to 12, the state-run news agency reported Wednesday.

The two suspects, who weren't identified, were detained in the city of Sanliurfa, near the border with Syria, on Saturday, the Anadolu Agency reported. A court in Istanbul charged them with premeditated murder and membership in a terror group on Wednesday, it said.

Ten Syrians were charged with membership in a terror group and ordered jailed pending trial on Sunday.

The suicide bomber set off the explosion near a group of German tourists on Jan. 12, just steps away from the landmark Blue Mosque, killing ten of them. Fifteen other people were wounded in the blast.

Turkish officials say the bomber was affiliated with the Islamic State group. No group has claimed the attack.

The bomber has been identified as Nabil Fadli, a Syrian national born in 1988 who had registered as a refugee with a migration agency in Istanbul a week before the attack.

Officials haven't disclosed any information on the suspects or say what links they have to the bomber.