Staring into the distance of South Sudan's volatile and sun-blasted borderlands with foe Sudan, Nyrop Nyol recounts the day soldiers came to her home and took her son away at gunpoint.

Four years after fleeing the flashpoint Abyei region-- a Lebanon-sized contested area claimed by both Sudan and South Sudan -- Nyol's eldest son was conscripted, most likely to fight in the border areas from which he had run.

"A lot of people were conscripted. As he could see other people in the village were being conscripted, he handed himself over to them," the mother of eight said of 17-year-old Daper, from whom she has not heard for a month.

"If a child refused to be conscripted, they were forced," she said, adding that soldiers had sticks to beat reluctant recruits and pointed guns to force people off public transport.

Abyei was due to hold a referendum in January 2011 to determine whether it would be controlled by Khartoum or Juba but the vote was stalled. In May, Sudanese troops seized the area, forcing more than 100,000 people to flee southwards.

"The last conscription started early in the morning when people were still sleeping," Nyol said.

"In the first conscription they were not looking for children, but the last conscription they were taking everybody," she added, glancing worriedly at her 13-year-old son who evaded capture along with his father.

Since then, the press gangs have been back twice looking for new recruits.

Nyol had hoped that Daper would finish his studies and become a doctor or teacher to better the meagre existence the family has endured since fleeing violence in Abyei in 2008.

It is not clear exactly who took Daper -- who has no military experience -- and Nyol just wants him back home.

But local administrator Kat Kuol said the Dinka Ngok people of Abyei who fled to South Sudan are being called up to fight for the homeland's "independence".

Headteacher Simon Manyuol says that soldiers came to Agok market, shut shops, chased men down the rutted mud streets and beat those trying to avoid being hauled into trucks.

"They come and push people and saying 'get up, get up!' and if you don't want to go they beat you and take you to the trucks," he said, a scar above his left eye marking his attempt to resist.

While he said some of the recruiters were not in uniform, others were from the ex-rebel turned official South Sudanese army.

"They say they are taking you for training and that you will go to fight in the Abyei border area," he added.

Those claims were rejected by the South Sudan's military spokesperson Philip Aguer, who said he was not aware of any large-scale conscription in the area, which is tense following recent bloody fighting.

Clashes broke out last month between Sudan and South Sudan along their undemarcated and disputed frontier, with each side blaming the other.

The fighting, which included ground troops as well as airstrikes, was the most serious since the South gained independence from Khartoum last July, after Africa's longest war.

As mediation efforts stumbled, Juba said Sudan had resumed border air strikes on Tuesday.

Months of African Union-led talks between the nations have failed to find agreement on border areas and vast oil revenues, with Juba demanding that any deal must include the handing over of Abyei to South Sudan.

Manyuol said he spent two days in a field along with around 3,000 other men before education officials came and got some teachers released, but as he left, more trucks were arriving.

"It was a mix of people who were happy and unhappy" depending on whether they had been unemployed or were taken from their jobs, he added.

Almost all of the 40 people taken who were working for international aid agencies have now been accounted for, but Manyuol said three of his friends are missing, including a headteacher, and some pupils.

"They did not differentiate the age and they were even taking children who were 9 or 10" before releasing those under 15, he said.

While Nyol says "the really young children" were returned to the village, others went in the hope of getting a better education.

"When we asked where they were taking them, they said they were taking the young ones to school," said Alueth Chol, whose brother and brother-in-law were conscripted while playing games at a local club.

Builder Nyaluer Nyok said the lack of men is affecting farming and construction work that the villages survive on, and worries how his family would cope if he was conscripted.

"When the soldiers came, I went from village to village hiding," he said. I fear that no one will take responsibility for my family and things here."