The US will only mediate a truce between Sudan's warring parties when they show they are “serious”, the State Department said on Thursday as Washington issued fresh sanctions on Sudanese companies after <a href="https://www.thenationalnews.com/mena/2023/05/31/sudans-army-suspends-ceasefire-talks-with-rsf/" target="_blank">the army left negotiations</a> in Jeddah. On Wednesday, the Sudanese Armed Forces <a href="https://www.thenationalnews.com/mena/2023/05/30/heavy-fighting-flares-in-sudan-shattering-first-day-of-new-us-and-saudi-mediated-truce/" target="_blank">blasted paramilitary Rapid Support Forces</a> bases after pulling out of the truce talks, accusing their rivals of breaching the armistice meant to bring in aid. The new US designations take aim at four companies, two that support the SAF and two that support the RSF. Those sanctioned include the Khartoum-based Defence Industries Corporation as well as the holding company Al Junaid Multi Activities Co. The White House said the sanctions would “ideally have a chilling effect on other countries who would engage with these four companies”. The US also issued visa restrictions on specific people in Sudan, including officials from the SAF, RFS and “leaders from the former Omar Al Bashir regime that have been responsible for or complicit in undermining Sudan's democratic transition”, a senior Biden administration official told reporters on a Thursday phone call. The official added these sanctions had been considered “long before” the SAF formally left negotiations. “We will not hesitate to take additional steps if the parties continue to destroy their country and thwart the resumption of a civilian transition,” they said. White House National Security Council Adviser Jake Sullivan called the warring parties' failure to abide by the ceasefire “appalling” and said Washington would work with its partners to “hold the belligerent parties accountable for their unconscionable violence”. “The ongoing fighting in Sudan between the Sudanese Armed Forces and the Rapid Support Forces is a tragedy that has already stolen far too many lives – it must end,” Mr Sullivan said in a statement. Meanwhile, Secretary of State Antony Blinken warned that the US was “looking at steps that we can take to make clear our views on any leaders for taking Sudan in the wrong direction”, he told reporters at Nato talks in Oslo. President Joe Biden last month issued an executive order that expanded US authorities' response to the violence in Sudan. The State Department added there had been “serious violations of the ceasefire by both sides”. “Once the forces make clear by their actions that they are serious about complying with the ceasefire, the United States and the Kingdom of Saudi Arabia are prepared to resume facilitation of the suspended discussions to find a negotiated solution to this conflict,” the US State Department said. “These violations have led us as a facilitator of these talks to seriously question whether the parties are ready to take the actions needed to meet the obligations they have undertaken on behalf of the Sudanese people.” Sudan's civil aviation authority said it will extend the closure of Sudanese airspace until June 15. “Aid and evacuation flights will be excepted from this decision after securing permissions from relevant authorities,” the authority said. In both north and south Khartoum on Wednesday, troops loyal to army chief Gen Abdel Fattah Al Burhan reportedly attacked key bases of the RSF, led by Gen <a href="https://www.thenationalnews.com/mena/2023/05/19/sudans-al-burhan-sacks-rsf-head-hemedti-as-deputy-of-sovereign-council/" target="_blank">Mohamed Dagalo</a>. One witness said there was “heavy artillery fire from army camps” in the capital's north, on the 47th day of a war that is believed to have claimed 1,800 lives, according to the Armed Conflict Location and Event Data Project. Another reported “artillery blasts on the RSF camp in Al Salha” in southern Khartoum – the largest paramilitary base and arsenal in the city. The attacks came two days after US and Saudi mediators said the warring parties had <a href="https://www.thenationalnews.com/mena/2023/05/29/khartoum-rocked-by-clashes-hours-before-sudan-truce-expires/" target="_blank">agreed to extend</a> the initial week-long humanitarian truce by five days. The mediators of the talks in Jeddah acknowledged repeated breaches but have held off imposing any sanctions. The UN says 1.2 million people have been internally displaced and more than 425,000 have fled to neighbouring countries.