Nairobi (AFP) - Eritrea on Monday accused arch-rival Ethiopia of attacking its heavily militarised border, but officials in Addis Ababa said they had no knowledge of the reported fighting.
Ethiopia on Sunday "unleashed an attack against Eritrea on the Tsorona Central Front," Eritrea's ministry of information said in a statement.
Ethiopian government spokesman Getachew Redda said there were "no clashes that we know of".
Eritrea won independence from Ethiopia in 1991 after three decades of war, but returned to battle in 1998-2000.
They remain bitter enemies, with their troops still eyeing each other along the fortified frontier. Tensions are never far from the surface.
"The purpose and ramifications of this attack are not clear," Eritrea said, adding it "will issue further statements on the unfolding situation."
Eritrea and Ethiopia have long traded accusations of attacks and of backing rebels to needle each other.
In February, Ethiopia accused Eritrea of being behind anti-government protests in the Oromia region last year which led to a violent clampdown by the government in Addis Ababa.
The two countries remain at odds over the flashpoint town of Badme, awarded to Eritrea by a United Nations-backed boundary commission but still controlled by Ethiopia.