March 16, 2012 -- Updated 1520 GMT (2320 HKT) Ethiopian government spokesperson Shimeles Kemal speaks in Addis Ababa on March 15, 2012. NEW: Eritrea says its neighbor staged a "provocative attack" on its soil The raid targeted posts used in attacks against Ethiopia, an Ethiopian official says The assault reignites tensions between the two African nations The ground assault Thursday struck bases used to launch attacks aimed at destabilizing Ethiopia, said Shimeles Kemal, an Ethiopian government spokesman. Such attacks are "organized, supported and financed by the Eritrean government," Kemal said at a news conference. The Eritrean foreign ministry described the incident as a "provocative attack" and said it was intended to divert attention from Ethiopia's continued "illegal occupation" of Eritrean territory. The raid "is part and parcel of the numerous unlawful and provocative attacks that have been going on intermittently in the past 10 years," the statement said. The military incursion was partly in retaliation to Eritrea backing groups responsible for atrocities in Ethiopia, the spokesman said, including a January attack that killed five Western tourists. Two other Germans were kidnapped in the northern region attack blamed on the Ethiopian rebel group, the Afar Revolutionary Democratic Unit Front or ARDUF, which the government accuses Eritrea of backing. Kemal said Ethiopia prefers to settle disputes with its neighbor through peaceful dialogue but stressed the nation will not 'hesitate to take proportional retaliatory action" if Eritrea launches more attacks. Before the war, it was classified as a province. CNN's Ashley Gallagher contributed to this report.