* Minister says reports of casualties, no details
* Gwadar is strategic port being developed with Chinese
* Chinese often stay at hotel, but none there during attack

Three gunmen attacked a luxury hotel in Pakistan's southwestern port city of Gwadar on Saturday, killing at least one guard and battling security forces from inside the building, security officials and the army said.

Balochistan Home Minister Ziaullah Langove said most guests had been evacuated from the five-star Pearl Continental Hotel, which helicopters circled as fighting was underway. He said there were reports of casualties, but did not give details.

The military said three gunmen killed a guard at the entrance to the hotel when they entered. Security forces had cordoned off the area and cornered the attackers in a staircase leading to the top floor, the military said in a statement

Gwadar is a strategic port on the Arabian Sea being developed as part of the $60 billion China Pakistan Economic Corridor, which is itself part of China's mammoth Belt and Road infrastructure project.

The hotel, located on a hillside in the port, is used by foreign guests, many of them Chinese project staff, but there were none in the building at the time of the attack, Langove said.

There was no immediate claim of responsibility.

Security across most of Pakistan has improved over recent years following a major crackdown after the country's worst attack, when some 150 people, most of them children, were killed in an attack on a school in the western city of Peshawar.

But Balochistan, the largest and poorest province, remains an exception and there have been several attacks this year.

The province is rife with ethnic, sectarian and separatist insurgencies, with several militant groups, including the Pakistani Taliban group Tehrik-i Taliban Pakistan (TTP), Balochistan Liberation Army and the Sunni group Lashkar-e-Jhangvi.