So, we are talking about venous intra-abdominal bleeding. From an iliac vein or inferior vena cava injury. If this is from a visible point check here how to fix it. If it is from an invisible hole carry on and read below.
The invisible hole
The concept is simple: make the invisible, visible. Do whatever you can to identify the bleeding point. Put something small, like your finger (s) on the bleeding area and press to stop or reduce the bleeding. Try to reduce the blood flow by clamping the relevant arterial vessel first. For example, if it is an iliac vein that bleeds, try first to clamp the relevant iliac artery (common, external) proximally and distally. If it is the inferior vena cava, clamp the aorta. This may reduce the bleeding and then see better the bleeding point. If there is something that interrupts your view to the bleeding point cut it until you see the bleeder. If it is an iliac artery do not hesitate. Arterial clamps up and down, cut in between and lift the two ends away to see the vein in the background. If you see the point just do what you would for venous bleeding from a visible point.
Avoid putting blind sutures somewhere in the bleeding area. It is more possible to cause other injuries than stopping the bleeding.