Beijing (CNN) -- A group of 18 Uighurs attacked a police station in the northwestern Chinese city of Hotan Monday, taking eight hostages and sparking a gunfight that left two of the hostages and 14 of the attackers dead, a regional spokeswoman said Wednesday.
The other six hostages were rescued; the four remaining attackers were taken into custody, said Hou Hanmin, the spokeswoman for China's Xinjiang Region.
"This is a planned attack," she said. "However, we do not know the identity of the attackers." Nor was the motivation of the attackers clear, she said.
The attackers carried a flag with "Holy War" written in Arabic on it, a regional spokeswoman said.
"We still need the police and relevant departments to further investigate which organization is related to the attack," Hou said.
Hou said the attackers carried an explosive device and a Molotov cocktail and set fire to the police station.
Xinjiang province was the site of ethnic violence in 2009 that killed nearly 200 people and wounded 1,800 others. Authorities blamed independence-seeking members of the Uighur ethnic group, a minority group of Turkic-speaking Muslims.
The 2009 violence came after long-simmering tensions between Uighurs and ethnic Han Chinese, who make up nearly 90 percent of China's 1.3 billion people.