In a speech to parliament on Thursday, Meles Zenawi, the prime minister of Ethiopia, blamed the current frontier stalemate on Eritrea.
He criticised Asmara for keeping the stance it held before the start of the war in 1998 by insisting it has the right to take by force territory it considers its own.
"The main reason and source of the border conflict ... is the arrogant and war-mongering invader that is the Eritrean regime," Meles said.
"Even now it is taking the same line by stating it has the right to take what it claims is occupied land by force," he said, noting that an international panel in December had blamed Eritrea for the start of the war.
"This position, which is the same as at the beginning of the war, is as the Claims Commission clearly pointed out, the stance of an invader," he said.
"This is the real source of the problem."
On 19 December, the Ethiopia-Eritrea Claims Commission, part of the Permanent Court of Arbitration in The Hague, ruled that Eritrea had broken international law in launching the attacks that sparked the war.
The commission rejected Eritrea's claim that the attacks were self-defence and said border disputes were not legal grounds on which to start a legitimate war, a point Meles seized on his speech.
"The main reason and source of the border conflict ... is the arrogant and war-mongering invader that is the Eritrean regime"
Meles Zenawi, the prime minister of Ethiopia
"Anyone with border claims must only address these claims peacefully and through dialogue and diplomacy, and never use force as an option," he said. "Anyone who does is nothing but an invader as the commission said."
Ethiopia and Eritrea have been trading bitter accusations of perfidy over the border for months, leading to a major escalation in tension and fears of a resumption of the conflict that claimed some 80,000 lives.