KHARTOUM (Reuters) - South Sudan's chief negotiator said on Sunday he had held successful meetings with Sudan's defense minister and other officials, in an attempt to resolve a border security dispute and restart southern oil exports, but gave no further details.

The two former civil war foes agreed at talks in Ethiopia in September to end hostilities and restart oil exports - including creating a demilitarized border zone - after coming close to war in April.

But the neighbors have been unable to agree how to withdraw their armies from the disputed border, a step both had said was necessary to resume oil exports from landlocked South Sudan through Sudanese pipelines.

On Sunday, South Sudan's chief negotiator Pagan Amum said he had met with Sudan's Defence Minister Abdel Raheem Mohammed Hussein as well as senior official Nafie Ali Nafie and others.

"The meetings were successful and we will continue to hold meetings," he Amum told reporters in Khartoum, without elaborating.

South Sudan seceded from Sudan last year after decades of civil war but unresolved issues have continued to fuel conflict.

South Sudan, which inherited three-quarters of oil production when it broke away, shut down its output of 350,000 barrels a day in January after tensions over pipeline fees escalated.

The new border tensions in the past two weeks have delayed a restart in production, originally scheduled for November 15, a serious blow to both crumbling economies.

(Reporting by Alexander Dziadosz and Khalid Abdelaziz; Writing by Alexander Dziadosz; Editing by Pravin Char)