URUMQI, China (Reuters) - Paramilitary police fanned out in the far-flung Chinese city of Urumqi on Wednesday to try to stifle unrest days after 156 people were killed in the region's worst ethnic violence in decades.
Han Chinese took to the streets for the second day running, and even with helicopters overhead there were scuffles in at least one crowd of about 1,000 as police appeared to seize ringleaders, prompting cries of "release them."
Urumqi, capital of the northwestern region of Xinjiang, imposed a curfew the previous evening after thousands of Han Chinese armed with sticks, knives and metal bars stormed through the city seeking revenge against Muslim Uighurs for Sunday's violence.
The instability prompted President Hu Jintao to abandon plans to attend a G8 summit in Italy and return home to monitor developments in energy-rich Xinjiang, where 1,080 people were wounded in rioting and 1,434 arrested.
Financial markets appeared unaffected and life was returning to the streets of Uighur neighborhoods.
Residents said night-time arrests were continuing and they had amassed collections of bricks and metal rods, and set up impromptu barricades to defend themselves against further Han attacks.
Officials played down the unrest as heavy security, including thousands of security forces and armed personnel carriers, brought peace to central parts of the city.
"Most of the public were quite restrained," Urumqi's Communist Party Boss Li Zhi said of Tuesday's violence.
"A handful of Han attacked Uighurs and there were a handful of Uighurs who attacked Han ... this handful of violent elements has been caught by the police and now the situation has been quelled," he added at a news conference in the Xinjiang capital.
There was no official curfew, although by early evening the streets were emptying and vehicles with bullhorns drove around telling people to "go home as quickly as possible."
The government has given no details of the number of injured on Tuesday or whether anyone was killed, and the lack of information was fuelling rumors.
A man in his 50s, who gave his name as Mohammed Ali, said he had heard from neighbors and friends that two men had died and two were seriously wounded. Others reported a higher toll.
"Now we are scared to go anywhere," Mohammed Ali told Reuters. "Doing even simple things becomes frightening."
The population of Urumqi, about 3,300 km (2,000 miles) west of Beijing, is mostly Han.
Some of the Uighurs' fears were borne out downtown. In one street, two young boys were surrounded by an angry Han mob, with dozens trying to pull them down and grabbing their hair.
In Washington, U.S. State Department spokesman Ian Kelly called for calm and urged China to uphold human rights.
"All sides should refrain from violence," he told a news briefing.
"While it's important that the Chinese authorities act to restore order and prevent further violence, we hope their actions will reflect respect for the legal rights of all Chinese citizens."
Xinjiang has long been a tightly controlled hotbed of ethnic tension, fostered by an economic gap between Uighurs and Han Chinese, government controls on religion and culture and an influx of Han migrants who now are the majority in most key cities, including Urumqi.
There were attacks in the region before and during last year's Olympics in Beijing.
The anger on both sides of the ethnic divide will make controlling politically and strategically sensitive Xinjiang all the more testing for the ruling Communist Party.
Groups of Han gathered around reporters in Urumqi to talk about how angry they were and dragged away a Uighur woman who also approached. Her fate was not clear.
"Uighurs are spoiled like pandas. When they steal, rob, rape or kill, they can get away with it. If we Han did the same thing, we'd be executed," said clothing store owner Li Yufang.
Li said he was outraged and wanted to protest again, but admitted it was unlikely with the heavy police presence.
Beijing cannot afford to lose its grip on the vast territory which borders Russia, Mongolia, Kazakhstan, Kyrgyzstan, Tajikistan, Afghanistan, Pakistan and India, has abundant oil reserves and is China's largest natural gas-producing region.
State media tried to dampen tension with editorials calling for calm and stories of Han and Uighur citizens helping each other during the violence. The government has not given a breakdown of the ethnicities of the dead.
"When ethnic harmony is destroyed it causes social turmoil and development halts," said an editorial in the People's Daily.
"Blood for blood is incompatible with the rule of law and will only lead to a vicious cycle of harm and revenge," the English-language China Daily commented.
The government has blamed Sunday's killings on exiled Uighurs seeking independence, especially Rebiya Kadeer, a businesswoman and activist living in exile in the United States.
Kadeer, writing in the Asian Wall Street Journal on Wednesday, condemned the violence on both sides and again denied being the cause of the unrest.
Uighurs, a Turkic people who are largely Muslim and share linguistic and cultural bonds with Central Asia, make up almost half of Xinjiang's 20 million people.
The Organization of the Islamic Conference, a grouping of 57 Muslim countries, on Wednesday urged China to investigate the violence and said Secretary General Ekmeluddin Ihsanoglu had contacted several member states and international organizations.
The U.N.'s top human rights official also called for Chinese authorities and ethnic groups to refrain from violence.
Neighboring Russia has put its support firmly behind China, saying the violence was a purely internal affair.
Additional reporting by Ben Blanchard in Shanghai, Emma Graham-Harrison and Benjamin Kang Lim in Beijing and Souhail Karam in Riyadh; Writing by Nick Macfie and Emma Graham-Harrison; Editing by Andrew Dobbie