Ethiopian troops pushed further into Eritrean territory towards a strategically important town yesterday, while in New York diplomats at the UN moved to impose an arms embargo on the warring parties.
"The battle is very intense. Our forces are advancing from the south trying to cut roads in order to encircle the town of Barentu," Ethiopian spokesman Mr Haile Kiros said. Thousands of civilians are reported to be fleeing the town.
The fighting had a direct impact on international aid deliveries for the first time yesterday. The UN temporarily pulled most of its staff out of the Gash Barka region after bombs fell near camps of displaced people.
Ethiopia is attempting to consolidate gains made in the early days of last Friday's surprise offensive. It has brought western journalists into a captured Eritrean town and into a camp holding 470 Eritrean prisoners of war.
Barentu is at the western end of the 620-mile disputed border between the two countries. Its capture would cut Eritrean supply lines linking the western region to the capital, Asmara. Both sides were yesterday transporting large numbers of reinforcements into the region.
There were also unconfirmed reports that Ethiopian troops were moving east towards the heavily fortified town of Zalambessa at the centre of the disputed 620-mile border.
Eritrean spokesman Mr Yemane Ghebremeskel played down the significance of the attack. "It doesn't matter if they make 10 or 15 kilometres. Our focus is to downgrade the offensive capacity of the enemy," he told The Irish Times.
Eritrea had shot down two Ethiopian SU25 fighter jets and 16 tanks, he said. "I can tell you our losses are in no way comparable to theirs," he said.
Current reports do not give a full picture of the fighting, as western media access has been limited to a small number of areas along the front. It is not known whether Ethiopian forces are enjoying the same success in other zones along the front.
Both sides have claimed to have killed large numbers of enemy troops but their figures have not been independently verified. However, Eritrea is thought to be suffering the heaviest casualties in the current offensive.
Both sides have routinely exaggerated their victories and played down their losses in the two-year -conflict. Before the current fighting, analysts estimated that a total of at least 20,000 had died on both sides.
Ethiopia, which has a population of 60 million, enjoys a distinct size advantage in the fighting over Eritrea, which has 3.5 million inhabitants.
Food distributions to an estimated 200,000 people have stopped. Providing assistance had become "difficult if not impossible", World Food Programme director Ms Catherine Bertini said.
A UN embargo on the supply of arms to either side looked increasingly likely last night as Russia dropped early objections to the proposal.
Britain and the US want a ban which would remain in place until both sides sign a peace agreement ending the war. Russia, which sold Ethiopia much of the military hardware being used in the fighting, dropped earlier opposition to the ban. Instead, it proposed a three-month embargo and was supported by France.
However, any embargo would have little immediate impact as both sides have built up massive military stockpiles. Further supplies could also be channelled through both countries' porous borders with unstable neighbours such as Sudan and Somalia.
Short-term gains have been made by both sides in the past but it is too early to tell whether Ethiopia's recent advances herald a definitive shift in the direction of the war.