Macedonian officials say two citizens have been arrested during a regional police operation against suspected Islamic extremists.

The head of Macedonia's secret service told reporters Thursday detained men are suspected of planning terrorist attacks, and of links with Islamic State group fighters returning from the Middle East. Mitko Cavkov did not specify where and when the alleged attacks were to have been carried out.

The suspects were arrested in Skopje and Kosovo on Nov. 4. Police in neighboring Albania and Kosovo have announced 13 arrests in their countries in joint operations with Macedonian authorities since Nov. 4, but none of the previously announced arrests were described as involving Macedonians.

All were for alleged illegal Islamic State-related activities.