A colony for 50 years, federated , Unified to Ethiopia , in 1991's seceded after three decades of rebellion. Since 1998 Eritrea is at War, harboring proxy warriors especially the notorious Al- Shabab. Torture ,imprisonment , thousands fleeing, no religious freedom , the only university is closed, everybody is in the army, No Parliament, No election, No functioning institution, No free press & all living journalists are in prison. Eritrea is called the North Korea of Africa.
Ethiopia "unleashed an attack against Eritrea on the Tsorona Central Front. The purpose and ramifications of this attack are not clear," the Eritrean government said in a short statement issued on Sunday night.
It does not mention any casualties.
Ethiopia's Information Minister Getachew Reda, who is out of the country, told the BBC he was not aware of the fighting.
As part of the Algiers peace agreement signed in 2000 both countries agreed to accept the ruling of an independent boundary commission over the location of the frontier as "final and binding".
But after the commission ruled that the disputed town of Badme was in Eritrea, Ethiopia at first refused to agree to the border demarcation and then called for dialogue before it would implement the decision.
Eritrea rejected this and as a consequence the countries have since been in a state of "neither war nor peace", says the BBC's Emmanuel Igunza in Nairobi.
Clashes at the border have happened in the past but they are rare occurrences.
Eritrea last month marked 25 years since it gained independence from Ethiopia after a long civil war