ASMARA - Eritrea accused arch-foe Ethiopia on Saturday of plotting to invade the Red Sea state ahead of a late-November deadline to mark their disputed border on maps.

Analysts and diplomats fear heightened tensions on the Horn of Africa rivals' frontier could erupt into a new conflict seven years after they fought a war that killed some 70,000 people.

In an online statement on Saturday, the Asmara government said its security agents had uncovered a plot by Addis Ababa.

"Intelligence agencies ... say that (Ethiopia) is intending to launch an invasion against Eritrea in the first week of November 2007 with the blessing of the U.S. Administration," the statement said.

It did not provide any evidence, but it said Ethiopia would prepare by withdrawing troops it has deployed in neighbouring Somalia to avoid "getting engaged along two fronts".

Ethiopian tanks and warplanes helped Somalia's weak interim government oust a hardline Somali Islamist movement -- a group seen by many as supported by Asmara -- in a war late last year.

Ethiopian government officials were not immediately available to comment on the latest allegation.

Addis Ababa and Asmara have been locked in a bitter border dispute since an independent boundary commission awarded Eritrea the key town of Badme in a 2002 ruling.

Ethiopia initially rejected that decision, saying it wanted more talks. Now Addis Ababa says it unconditionally accepts the ruling, but still wants more discussion on implementation.

Frustrated by the lack of progress, the commission said last November that it was giving the two countries one more year to to mark the frontier physically, or it would mark the boundaries on maps and let them stand.

At a commission meeting in September, Ethiopia and Eritrea traded recriminations, accusing each other of violating the 2000 Algiers agreement that ended the 1998-2000 war.

Addis Ababa has threatened to pull out of the pact, saying Asmara breached the deal by sending thousands of troops into a demilitarised zone on the Eritrean side of the border.

Asmara says Addis Ababa is using the border issue to cover up internal strife.