At a news conference in Khartoum, the newly-elected leader of the Alliance of Eritrean National Force, Abdullah Idriss, said they would use all means neccessary to overthrow the government of Eritrea.

He accused Mr Aferworki of being a dictator and said he had created enemies for the country and mismanaged the economy.

The BBC correspondent in Khartoum says the open welcome given to the group in Sudan is a tit-for-tat policy since Khartoum has accused Eritrea of supporting Sudanese opposition forces.

From the newsroom of the BBC World Service

The representatives of the ten Eritrean groups, which have been meeting in Khartoum, called on the Eritrean people to work for a speedy end to what they termed the 'Afeworki dictatorship'.

A statement issued by the ten, and which was read at a news conference this morning in Khartoum, said the ten groups had formed a united body called the Alliance of Eritrean National Force, to continue the struggle against the EPLF government in Asmara.

They said they had elected Abdallah Idriss as the head of the new alliance. Idriss heads the Eritrean Liberation Front (ELF), the first Eritrean group formed in the early 60's to spearhead the struggle for Eritrean independence. The ELF has over the years split into several groups, one of which is the ruling EPLF in Asmara.

Idriss accused Afeworki's regime of destroying the economy of Eritrea, damaging its ties with the neighbours, and establishing a vicious one-man dictatorship.

"We will employ all means, including the military option, to get rid of the regime in our country," Idriss said.

He revealed that the alliance is working to replace Afeworki's regime with a government that is democratic, respects human rights, and is for multi-party politics.

The holding of the meeting of the Eritrean opposition groups in Sudan, and the press conference they held in Khartoum, indicates a radical change in the attitude of the government here.

For years the government of General Bashir has accused Afeworki's regime of providing all kinds of support to the opposition NDA. But it did not take reciprocal action, at least not openly.

Now that has changed. The news conference took place at the governments own al-Zubair International Conference Center in Khartoum.

``The statements of Eritrean officials and the actions of the Eritrean army on the ground prove that so far there has been no change of heart,'' Ethiopia said in a statement in the capital, Addis Ababa.

``(Eritrea) is simply trying to buy time to regroup and reorganize in order to retain the Ethiopian territories that it continues to occupy to this day and to regain Badme,'' added the statement from the office of the government spokesperson.

Eritrea accepted the OAU's proposals to end the conflict on February 27 after refusing to even discuss it for months. The proposals call for Eritrea's withdrawal from Ethiopian territory it occupies followed by talks leading to a lasting solution.

Saturday, Ethiopia said that Eritrea still occupied large chunks of its territory. It claimed it had driven Eritrean forces from the disputed Badme area, while Eritrea insisted that it had only ``tactically withdrawn from Badme.

``While Eritrean forces have been kicked out of Badme, they still occupy Ethiopian territory that they captured during their invasion of Ethiopia last year, the statement said. ``They continue to occupy the Zalambessa-Aiga region, the Bada-Bure region and Egala region (near Tsorona).''

``The Eritrean government has shown no signs of withdrawing its army from these territories, as it is required to do by the OAU,'' the statement said.

In the Etritrean capital Asmara, Eritrea said in a statement that it was committed to the OAU formula of returning peace to the Horn of Africa and had always called for an immediate cease-fire and cessation of hostilities.

It added that Eritrea had established a high-level body to implement the framework agreement but did not say whether it would withdraw from the disputed territories. Eritrea has previously said the question of withdrawal does not arise because the territories were historically Eritrean.

Ethiopian forces last week drove Eritrean troops out of the contested border region of Badme -- occupied by Eritrea since last May -- in a huge infantry offensive backed by artillery and fighter planes. Eritrea said soon after that it agreed to the OAU peace plan, that also has the backing of the United States.

In a statement on the disputed border situation, the Addis Ababa government said "Eritrean troops continue to occupy the (northern) Zala Anbesa-Aiga region, (northeastern) Bada-Bure region and (northern) Egala region."

"The Eritrean government has shown no signs of withdrawing its army from these territories, as it is required to do by the OAU," added the statement from Addis Ababa, which last weekend claimed a "total victory" after the fall of Badme and a letter from Eritrea's President Issaias Afeworki to the UN Security Council finally accepting the peace plan from the Organisation of African Unity (OAU).

An official Ethiopian source said that at the beginning of last June, a month after simmering tensions erupted into a border war, troops from the Horn of Africa countries clashed in the Aiga and Indalgeda regions, between 190 and 200 kilometres (about 125 miles) northeast of Mekele, the capital of Ethiopia's Tigray province.

The fighting was headed towards the Alitena zone, 185 kilometres (115 miles) from Mekele. Alitena is one of the territories claimed by Ethiopia, together with the Badme, Tsorona and Bada regions, on the basis of maps drawn up by Italian colonists.

Zala Anbesa was last June 24 the scene of heavy artillery exchanges between the two sides before a relative calm in the fighting, which was then broken by ferocious battles from February 6, notably on the Badme front, which claimed thousands of lives, according to both sides.

Egala, close to Gerahusirnay and not far from the northern Tsorona front, has also seen recent conflict.

In mid-January, Addis Ababa accused Eritrean troops of moving into Ethiopian territory the previous month and carrying out artillery attacks, independent sources told AFP. Hand-to-hand fighting was reported in the Gerahursirnay region.

Saturday's government said: "The Eritrean army is making frantic efforts to further reinforce its trenches along these lines and mobilize additional troops to thse areas."

The government considered that a "careful reading" of Eritrean statements, notably those issued by Foreign Minister Haile Woldetensae, indicated that in spite of the acceptance of the OAU plan, Eritrea is preparing "to launch, after some readjustments, a heavy attack."

The Asmara authorities have not officially informed Eritrean people of their acceptance of the plan, which notably calls for the withdrawal of troops to their pre-war positions, the deployment of an international force and independent delineation of the controversial frontier line.

After the recent fighting and the fall of Badme, the Asmara authorities spoke of a "tactical withdrawal in order to regroup and launch a successful offensive", the statement from Addis Ababa said.

It deplored the fact that the international community had failed to "act vigorously" to have Eritrea "withdraw from the occupied territory unconditionally".

Ethiopian authorities stressed that "Ethiopia has never had and does not have any designs on the sovereignty of Eritrea. Ethiopia has never rejected peace but was forced into war by Eritrean aggression and intransigence".

Though Eritrea accepted an Organization of African Unity proposal to end the war last week, Ethiopia says Eritrea has shown no sign of withdrawing its forces from the disputed territory. Instead, Eritrea seemed to be sending in reinforcements, Ethiopian government spokeswoman Selome Tedesse said Saturday.

Ethiopia says it drove Eritrean forces from northwestern Badme a week ago. However, Eritrea still occupies territory in the southern and eastern areas of their border.

"It must not be forgotten that thousands of Ethiopians continue to endure Eritrean occupation and that sovereign Ethiopian territory still remains in Eritrean hands," she said.

The Horn of Africa neighbors are fighting over parts of their barren 1,000 kilometer (620-mile) border that were never clearly demarcated when Eritrea became independent from Ethiopia in 1993.

The latest fighting in the war that began in May 1997 broke out Feb. 6 and ended an eight-month stalemate after full-scale war killed 1,000 people in May and June.

Until the recent Ethiopian offensive, Eritrea had refused to agree to a key point in the OAU proposal, that it withdraw its troops from contested areas to facilitate negotiations.

"It is simply trying to buy time to regroup and reorganize to retain the Ethiopian territories that it continues to occupy to this day and to regain Badme," Selome said.

Comment from Eritrea was not immediately available.