Vietnam has declared a California-based exile group a terrorist organization after 15 local members were convicted in a failed bombing of the country's largest airport.

The attempted attack at the Tan Son Nhat airport in Ho Chi Minh City in April caused a scare but no casualties. The communist government linked it to the Provisional Central Government of Vietnam, an exile group little known locally but tied to the defeated U.S-backed South Vietnamese republic.

The Ministry of Public Security said in a statement Wednesday that the group is a terrorist organization and those associated with it will be dealt with in accordance with law.

Another group, the California-based Vietnam Reform Party or Viet Tan, was declared a terrorist organization in 2016 and was accused of sending arms and planning attacks.