Greece’s anti-terrorism service raided apartments in central Athens on Tuesday, detaining nine people for questioning on suspected of links to a far-leftist militant group outlawed in Turkey, police said.

“So far nine people have been detained, they are Afghans and Kurds based on their identity papers. Police found jars containing unspecified explosive material, cables to connect to detonators and laptops,”a police official told Reuters.

A second police official confirmed authorities were probing links to DHKP/C, an outlawed group blamed for attacks and suicide bombings in Turkey.

The operation was ongoing, the official said.

Turkish President Tayip Erdogan is expected to visit Greece in December. [Reuters]