Authorities on Saturday announced the first arrest in a bombing that killed at least 43 people in China's Muslim northwest and said they were launching a yearlong anti-terrorism crackdown.
Police announced names of five people blamed for Thursday's attack in a vegetable market in the city of Urumqi, and accused them of forming a "terrorist gang" at the end of 2013, the official Xinhua News Agency said. Four of the suspects were killed and the fifth was captured Thursday night in an area about 250 kilometres (150 miles) south of Urumqi, Xinhua said.
The group "took part in illegal religious activities, watched and listened to terrorist violence video and audio materials," according to the news agency.
It said an anti-terrorism campaign with Xinjiang "as the major battlefield" started Friday. Authorities would target religious extremist groups, gun and "explosive manufacturing dens and terrorist training camps."
"Terrorists and extremists will be hunted down and punished," Xinhua said.
Also Saturday, the city government in Beijing, the Chinese capital, announced it was tightening security on subways.
A measure under which passengers at stations in central Beijing are required to undergo security checks will be extended to three additional stations, the city government said. Passengers at all stations already are required to submit handbags and parcels for X-ray examination under measures imposed ahead of the 2008 Summer Olympics in Beijing.
Chinese authorities have blamed most recent attacks on radical separatists from the country's Muslim Uighur minority.
Xinjiang is home to the native Turkic-speaking Uighurs (pronounced WEE'-gurs) but has seen large inflows from China's ethnic Han majority in recent decades.
Uighur activists contend that restrictive and discriminatory policies favouring the Chinese migrants are fueling the bloodshed. The knowledge that Muslims elsewhere are rising up against their governments also seems to be contributing to the increased militancy.
The violence was the deadliest in Xinjiang since riots in Urumqi in 2009 between Uighurs and Hans left almost 200 people dead, according to an official death toll. Thursday's attack also was the bloodiest single act of violence in Xinjiang in recent history.
Recent attacks show an audaciousness and deliberateness that wasn't present before. Attackers increasingly target civilians rather than police and government targets.
A bomb attack at an Urumqi train station as President Xi Jinping was visiting the region last month killed three people, including two attackers, and injured 79. Security has been tightened since then.
In response to Thursday's attack, Xi pledged to "severely punish terrorists and spare no efforts in maintaining stability," Xinhua reported.
China's top police official, Public Security Minister Guo Shengkun, was dispatched to Urumqi as the head of a team to investigate the attack.