South Sudan says at least 3,000 troops from neighboring Sudan have entered its territory, as tensions rise between the countries.
Southern army spokesman Philip Aguer says the troops entered the town of Kuake in Upper Nile state on Saturday. He says the alleged incursion violates a 2012 cooperation agreement that led to both countries pulling their forces from disputed border areas.
On Saturday, Sudanese President Omar al-Bashir ordered a shutdown of a pipeline that carries South Sudanese oil through the country for export. Bashir said the move is in response to South Sudan's funding of rebels fighting his government.
A South Sudanese government spokesman, Barnaba Marial Benjamin, said on Monday the accusation is not true.
"The reason they give, that we hear publicly though the press, is that we are supporting the rebels in their own country. That is, Southern Kordofan and Southern Blue Nile. This is their internal issue. It has nothing to do with us whatsoever," he said. "They want to find a scapegoat, so all they do is say, 'Oh this is South Sudan.' Of course there is no justification in what they are saying."
Sudanese officials appeared to soften their stance Sunday, saying the disagreement could lead to nine economic and security agreements being suspended, but that such a move could take time to implement.
There was no indication Monday the pipeline had been turned off.
Sudan and South Sudan signed the agreements last year to resolve issues over oil and borders stemming from the South's independence in July 2011. The split followed a 21-year North-South civil war.
Land-locked South Sudan must export its oil to international markets through pipelines owned by Sudan that run through its territory.