Utilization of itc on purchases meant for sales to sez unit

Hello,

My client does interstate (IGST) material purchases and then sells the material to SEZ without payment of IGST and also to Regular Non SEZ clients. Questions that i have are:

1.  As the sales to SEZ are being made without payment of IGST does my client has to file the LUT or ask the SEZ to file and provide the LUT copy to my client?

2.  Can my client utilize the ITC on the purchases meant for supply to SEZ to discharge IGST liability towards sales made to Regular Non SEZ clients?