LINKEDINCOMMENTMORE

ADDIS ABABA, Ethiopia -- Ethiopian forces entered archrival Eritrea on Thursday and carried out what a government spokesman described as "a successful attack" against military posts.

Government spokesman Shimeles Kemal said Ethiopia launched the attack because Eritrea was training "subversive groups" there that carried out attacks inside Ethiopia.

Ethiopia and Eritrea fought a border war from 1998 to 2000. Tensions have reignited between the countries in recent months.

No details about the military operations or any damage or casualties caused were immediately released.

The "Eritrea government has continued launching attacks at Ethiopia through its proxy groups. The attacks had continued. And the recent attacks against European tourists is one of the reasons for the retaliation," Shimeles said.

Militants attacked European tourists from five nations traveling in Ethiopia's arid north in January.

Five tourists were killed and two were kidnapped. The two kidnapped German tourists have since been released.

Ethiopia blamed gunmen from Eritrea for the attack.