He said the hundreds of thousands of troops dug in along both sides of the the 1,000-kilometre (600-mile) -long frontier were engaging in "intermittent exchange of artillery fire."

The Eritrean army had been on maximum alert for the past 12 days, he added.

The prime minister also disclosed, for the first time, that foreign military experts were in Ethiopia to train pilots and carry out maintenance, and said he assumed Eritrea was also using foreign experts.

Those here are believed to be Russians or Ukrainians, a diplomat said.

At the border, he said, there was a "very high level of tension that can get out of hand easily and at any time."

He described the situation as "no war, no peace," but said of resumed fighting: "It could be any day."

Ethiopian authorities have banned travel to the border regions of Tigray and Afar by parliamentarians and non-residents, Meles said.

Tourism in the border region was suspended last week, and most schools there have closed.

Eritrean President Issaias Afeworki meanwhile said his country would "never fire the first bullet" against Ethiopia, and "remains engaged in the OAU (Organisation of African Unity) peace process," the Eritrean agency ERINA reported earlier Tuesday.

Eritrea "will stick to a peaceful settlement of the dispute until the last second," Afeworki added in a communique sent by ERINA to AFP in Nairobi.

"The OAU Framework Agreement is not a take-it-or-leave-it package but an open-ended peace proposal subject to discussion and clarifications," he said, referring to an OAU peace plan advanced in November.

Afeworki also charged that "Ethiopia continues its policy of intimidation and blackmail, letting it be known that it has finished its preparations and is about to launch war."

Conflict over the ill-defined border erupted in May last year.

Reliable reports said that early battles left several thousand dead, and hundreds of thousands of civilians living along the border have been displaced.

Fighting at close quarters tapered off in June, when the two sides also agreed to a US-brokered pact to halt airstrikes, but early attempts by the United States and Rwanda to broker peace failed.

The OAU's 11-point peace plan presented in November provides notably for the withdrawal of Eritrean forces from positions they occupied at the start of the conflict, the six-month deployment of a peacekeeping and observation force, and neutral delineation of the ill-defined frontier.

Ethiopia announced it had accepted that plan, and the OAU last week respondend to 29 questions Asmara posed on it.

Diplomatic efforts to resolve the conflict continue, with former French cabinet minister Jean-Francois Deniau visiting Asmara and holding a second round of talks in Addis Ababa on Tuesday with Meles before leaving for Djibouti, which borders both countries, and which hosts France's biggest military base in Africa.

UN special envoy Mohamed Sahnoun is also undertaking shuttle diplomacy this week.

The diplomats are trying to persuade Eritrea to accept the OAU plan, and urging Ethiopia not to resort to war, the prime minister acknowledged.

"We hope we can get a response from Eritrea," OAU spokesman Ibrahim Dagash told journalists here Tuesday. He said no deadline had been set, but "the matter is very urgent."

But Meles said he was not optimistic, and reaffirmed Ethiopia's position that any negotiations must be preceded by an Eritrean military withdrawal.