German police have confirmed that two people have been arrested during raids, on 11 properties in Berlin, connected to a local Islamist terrorist cell.

The two, of Turkish origin, were allegedly planning to join Islamist groups in Syria to commit "a serious act of violence", according to Berlin's general prosecutor's office.

Ismet D., 41, was the self-styled "Emir" of the group, which consisted of Turkish and Russian citizens of Chechen and Dagestani origin. The other man arrested, 43-year-old Emin F., was tasked with finding funds for the operation.

Meanwhile, the development came after Belgium officials said that the anti-terror operation, in which two suspected Islamist militants were killed, was over.

The two men died in a bloody shootout in the eastern town of Verviers, near the German border, after they opened fire on police. Police said that the terror cell was on the verge of committing large-scale attacks in the country.

"This operational cell of about 10 people, some of whom had returned from Syria, was on the point of launching significant terrorist attacks in Belgium," Thierry Werts of the Belgian federal prosecutor's office told a press conference in Brussels.

"During the search, certain suspects immediately opened fire at special forces of the police with automatic weapons. They opened fire for several minutes. Two suspects were killed and a third was arrested."

Meanwhile, around a dozen people have been questioned overnight in Paris over a possible logistic support to the Kouachi brothers who killed 12 people at the headquarters of satirical magazine Charlie Hebdo.