Myanmar’s security forces arrested 39 people for allegedly perpetrating attacks and planning to join rebel groups to receive military training, EFE reported.

The arrests began Apr. 17 in Yangon during a raid on the home of an opponent of the Feb. 1 military coup, where authorities found ammunition, detonators and fuses for explosives.

The police investigation said these first arrests are linked to a series of explosive attacks that occurred in the former capital against government offices, although no group has claimed responsibility for the incidents.