Transit in Urumqi with Czech Republic passport

Hi,
I am flying from Islamabad to Almaty (Kazakhstan) with 2h 25min stop in Urumchi, flying with China Southern, all route is in one ticket.
I am holder of service passport of Czech Republic, alternatively I can use my normal passport. I need to know, if I need to obtain visa for stay in Urumchi, if my transit time is more than 2 hours. I don't plan to leave the airport, I will stay in transit zone.

Thanks a lot for your help.

Itinerary:
CZ6008
Thu 23 Nov
10:15 Islamabad , Benazir Bhutto International (ISB)
16:05 Urumqi , Diwopu International (URC)
Connecting time
2h25m

CZ6011
Thu 23 Nov
18:30 Urumqi , Diwopu International (URC)
Terminal 3
18:20 Almaty , International (ALA)