MOSCOW (AP) — Russia's Federal Security Service says a group of Central Asian citizens have been arrested on suspicion on planning attacks in the Moscow region and that explosives and weapons have been seized.

The security service, known by the acronym FSB, said the suspects were under the direction of unspecified "international terrorist groups" active in Syria and Turkey.

An FSB statement reported by Russian news agencies Wednesday gave few details, including where those arrested were from. Concern is high in most former Soviet Central Asian states about the potential for the spread of Islamic extremism.

The statement didn't specify where the alleged attacks were planned for, or when, other than saying "the May holidays."

Russia observes May Day and May 9 is Victory Day, marking the defeat of Nazi Germany.