Image caption The south says it wants a UN peace force to monitor the border

Ethiopia has offered to send peacekeepers to Sudan's disputed border region of Abyei after its recent seizure by northern troops.

Analysts have feared the Abyei dispute could reignite the civil war between the north and South Sudan, which is due to become independent in July.

Officials say the south has accepted the offer; the north is considering it.

It comes after both sides agreed to set up a demilitarised zone along their border to be jointly patrolled.

Sudan expert Alex De Waal, who is has been working on the African Union-mediated deal, told the BBC negotiations about how it would work were ongoing.

Some 1.5 million people died in the 22-year north-south civil war which ended in 2005.

Border force request

The UN Security Council condemned the occupation of Abyei and called for the immediate withdrawal of northern troops from the oil-producing region also claimed by the south.

Analysis on demilitarised zone This agreement sets up a joint political and security mechanism as well as a demilitarised zone 10km either side of the border line. It provides a mechanism for allowing the Sudanese army to leave Abyei and it also provides the structure on to which a possible third party could be locked. What is under discussion now is what form that third party should take: Should it be the UN, should it be another third party, should there be troops to protect those monitors or should those monitors be protected by the parties themselves? At the moment the trust between Sudan and South Sudan is not really there but what is quite remarkable is that when the soldiers get together, they get down to business. The business-like and co-operative approach of the senior military officers on both sides gives a lot of reason for confidence that they will actually sort it out.

But Sudan's ambassador to the UN Daffa-Alla Elhag Ali Osman has said it will do so only when new political and security arrangements have been agreed.

Meanwhile, he said Sudan's government wanted peacekeepers to leave its territory when South Sudan becomes independent in July.

The request comes after UN chief Ban Ki-moon proposed a three-month extension to the force's mandate while the north and south resolve outstanding territorial issues.

Mr Osman told the UN Security Council such issues could be settled at the negotiating table.

But a senior official from South Sudan, Ezekiel Gatkuoth, said the UN should have a presence on both sides of the border.

He welcomed its continued existence in the south, saying its main objective should be to avoid a security vacuum.

"We were asking for [a] more than 7,000 UN peacekeeping force. Then we have asked for the UN to do a consultation with the governors of southern Sudan so that we can have a new mission with responsibility to monitor the border and also protect civilians," he told the BBC's World Today programme.

The BBC's Barbara Plett in New York says it is not clear how the UN Security Council will respond to Khartoum's request.

Limiting peacekeepers to the south could complicate efforts to monitor the boundary, parts of which, including Abyei, are contested.

As the Security Council debated the UN's mission in Sudan, Ethiopia said it would send peacekeepers to Abyei if both north and south made the request.

"It is within our interests and that of the region to maintain stability in Sudan," foreign ministry spokesman Dina Mufti told Reuters news agency.

Mr Gatkuoth said Juba accepted Ethiopia's proposal, but Mr Osman said Khartoum was still considering it.

Abyei is claimed by a southern group, the Dinka Ngok, and northern nomads, the Misseriya.

Under the 2005 peace deal, which ended the 22-year civil war, Abyei was granted special status and a joint administration was set up in 2008 to run the area until a referendum decided its fate.

That vote was due to take place in January, when the south decided to split from the north, but has now been postponed indefinitely.

Last week, South Sudan's humanitarian affairs minister said he estimated 150,000 people had fled from Abyei state and border regions fearing further attacks. The UN's currently overall figure is 60,000.