Just want to share my experience and alert other travellers to Khartoum.
I have been to Khartoum like 7 or 8 times. I have a good impression of the customs and immigration until now.
At the security check after immigration, normally they just let you pass. This time they check everyone, even Sudanese. They took me into the cubicle normally used to body search women. These guy continue to speak in Arabic and mentioned US$. I sense he wanted me to show him my US$ and he will take a large amount. I said "little US$" and took out all my remaining SDG and gave it to him and I moved out. I gave him SDG100 (about US$33)
The incident is like a robbery. The guy was holding on to my passport and boarding pass. If I had taken out my pouch with the US$, I am sure he would take a few hundreds from it. Fortunately, the cubicle is too small. If it is big, he could have search my bag. I think this is not organised as a big scale, otherwise they could take me to a big room and search my bag for money.
So, be careful with your money. If they search your bag and find money, they will take it.
I understand this is due to the country's financial situation. The central bank has given instructions to stem the outflow of money. But, even so, all checks should be done in an open area and the process should be transparent.
This may be some individual trying to make a quick buck but it is bring the country some very bad name. As an potential investor (employee), I don't want to go back again.