Sudan has put a fresh obstacle in the way of allowing its land-locked southern neighbour to pipe its oil to the Red Sea, South Sudan’s president Salva Kiir said on Monday, dashing plans to re-start production after 11 months and unsettling last year’s still fragile peace agreement.South Sudan took over the national oil company when it seceded last year but left the northern state with 25 percent of the oil fields which straddle their border as well as the sole pipeline to Port Sudan and the adjacent refinery.In January South Sudan shut down its entire oil output of 350,000 barrels a day after tensions with Sudan over oil fees escalated but an agreement to re-open the export pipeline was announced in September.But Kiir said on Monday Sudan had now demanded as a new condition for reopening the pipeline that South Sudan now disarm rebels of the Sudan People’s Liberation Movement North (SPLM-North) which operate in two states bordering South Sudan."It is an impossible mission which our brothers in the government in Khartoum would want us to undertake. Because of this Khartoum authorities have refused to accept passage of South Sudan oil through their territory to market,” he told a meeting of government officials in Juba which was attended by Reuters."We are a different country, SPLM-North is in a different country. You cannot imagine that a foreign army can cross to another country to go and conduct disarmament. That can’t be. It will not happen,” he said.South Sudan denies supporting the SPLM-North, which plans together with rebels from the western region of Darfur to topple Sudan’s veteran president Omar Hassan al-Bashir.Juba denies it supports the SPLM-North in the South Kordofan and Blue Nile states but diplomats say such support is likely in retaliation for suspected Sudanese backing for anti-government militias in South Sudan.Kiir said he spoke to Bashir two days ago by phone to restart border security talks."He (Bashir) assured me that he is going to direct the minister of defence to write now an invitation letter to our team in Juba so that they go to Khartoum to start negotiations,” he said."When we signed the cooperation agreement (in September) we thought it was going to be implemented unconditionally. Now it appears that we have to renegotiate its implementation again. We will do all that it takes to maintain peace between our two countries and avoid any return to war,” he added.