Exclusive: The United States is withholding a visa for Sudanese army chief Abdel Fattah al-Burhan ahead of his scheduled UN appearance in a move that Sudanese and other sources say is linked to a US-backed ceasefire proposal that Khartoum has resisted ↧ EXCLUSIVE: US ties Sudanese army leader's UN visa to ceasefire plan... The United States is withholding a visa for Sudanese army chief Abdel Fattah al-Burhan ahead of his scheduled UN ​appearance in a move that Sudanese and other sources say is linked to a US-backed ceasefire proposal that Khartoum has resisted.