The Tigray People's Liberation Front (TPLF) have said troops from neighbouring Eritrea have launched a "full-scale offensive".
The TPLF has been battling Ethiopian federal forces and their allies for nearly two years.
Eritrean troops entered Tigray to back the Ethiopian military after fighting broke out in November 2020 before withdrawing from most areas last year.
“Eritrea is deploying its entire army as well as reservists. Our forces are heroically defending their positions,” Getachew said.
Reuters was not immediately able to verify the account on Twitter from Getachew Reda, a spokesperson for the Tigray People’s Liberation Front (TPLF).
If confirmed, the offensive would mark an escalation in a war that has displaced millions and triggered a humanitarian disaster across northern Ethiopia.
Getachew said Ethiopian troops and special forces from the Amhara region had also joined the offensive.
The conflict in Tigray re-erupted on 24 August, breaking a ceasefire in place since March. Earlier this month, Tigrayan forces said they were ready for a ceasefire and would accept an African Union-led peace process.
The Tigray conflict has its roots in tensions that go back generations in Ethiopia.
The country is made up of 10 regions -- and two cities -- that have a substantial amount of autonomy, including regional police and militia. Because of a previous conflict with neighboring Eritrea, there are also a large number of federal troops in Tigray. Regional governments are largely divided along entrenched ethnic lines.
Before Abiy Ahmed came to power, the TPLF had governed Ethiopia with an iron grip for decades, overseeing a period of stability and economic growth at the cost of basic civil and political rights. The party's authoritarian rule provoked a popular uprising that ultimately forced Abiy's predecessor, Hailemariam Desalegn, to resign.
Read more at the Guardian