Pakistan has complained to neighbouring Iran that such militant groups are active along their shared border but that Tehran has taken no action.
The Pearl Continental in Gwadar is a popular accommodation and meeting place for business travellers, many of them connected to the ambitious development and transportation project there that is a centerpiece of Beijing's burgeoning economic and political alliance with Pakistan.
China has invested a reported US$60 billion in Pakistan, especially the Gwadar deep port on the Arabian Sea, to open and upgrade transport, infrastructure and communication links with far-western China.
The Balochistan Chief Minister, Jam Kamal Khan, condemned the attack and ordered security forces to place a high priority on ensuring the safety of all guests at the hotel.
Balochistan, a vast desert province, has been plagued with political violence for years. It is the home of several different ethnic and tribal militant separatist groups, as well as Islamist militants that have attacked churches.
Pakistani officials have also accused India of sending spies to infiltrate the region. India denies the claims.