A blockade along the border between north and South Sudan is causing a shortage of goods in the south, a southern minister has told the BBC. Northern officials deny the Khartoum government has closed the border. South Sudan is due to become independent in July and relations with the north are strained. The two sides are to resume separation talks but disagreement remains on sharing oil revenues and the border region of Abyei, claimed by both. Luka Biong, a southern minister in the federal government, told the BBC the border blockage was making life very hard for the southern states near the internal border. Despite Khartoum's denial of any sort of economic embargo, there are many reports of trucks being stopped from travelling to the south. Mr Biong said in the short term the blockage would hurt South Sudan, but in the long term it would damage the northern economy as southerners would look to supply themselves elsewhere. Some southern leaders have accused President Omar al-Bashir's National Congress Party of closing the border, though the party denies this. Mr Biong was more cautious, saying it could be a policy or the behaviour of isolated individuals at the local level. Whatever the case, the situation is further degrading the relationship between the two parts of the country. The two sides are due to resume critical pre-separation negotiations on Thursday but there is still substantial disagreement on issues such as oil and citizenship and about the border region of Abyei. Source: BBC