By WILLIAM FOREMAN

URUMQI, China — China’s top communist leaders have declared that ethnic riots that killed over 150 people this week in the west of the country were orchestrated by overseas forces and vowed to maintain stability in the aftermath, state media said Thursday.

The nine-member Politburo met Wednesday, led by President Hu Jintao, and called on Communist Party members and officials at all levels to mobilize to restore order, and promised punishment to rioters and leniency to participants who were misled by agitators.

“Preserving and maintaining the overall stability of Xinjiang is currently the most urgent task,” the Politburo said, according to an account carried by the official Xinhua News Agency.

Security forces kept a firm grip on the tense Xinjiang capital, Urumqi (pronounced uh-ROOM-chee) Thursday, as residents tentatively emerged to go about daily life.

Red red stickers were up outside apartment compounds saying, “Don’t listen to any rumors” and “Keep calm and maintain public order.”

Crowds of Han Chinese, China’s dominant ethnic group, cheered as trucks full of police and covered in banners reading, “We must defeat the terrorists” and “Oppose ethnic separatism and hatred,” rumbled by.

Officials have said 156 people were killed and more than 1,100 people hurt as the Turkic-speaking Uighurs ran amok in the city on Sunday, angry over the deaths last month of Uighur factory workers during a brawl in southern China.

The Uighurs (pronounced WEE-gers) say security forces gunned down many of Sunday’s protesters. Officials have yet to give an ethnic breakdown of those killed.

In response to the riot, hundreds of Han Chinese rampaged through the city Tuesday with sticks and meat cleavers, looking for Uighurs and revenge.

Residents of Xinjiang can expect a full-bore propaganda campaign in the coming days.

The meeting of the Politburo — China’s most powerful body — took place shortly after Hu, also head of the Communist Party, returned after cutting short a trip to Italy to participate in a Group of Eight summit.

“In particular, we must emphasize the thinking of stability above all else to the cadres and masses of all ethnic groups in Xinjiang,” the Politburo said, according to Xinhua.

It instructed cadre to pursue tough punishment for rioters who committed “serious criminal acts of beating, smashing, looting and burning.”

“We must by law severely attack those hard-core elements who planned and organized this incident and seriously violent criminals,” the Politburo said. It also called for “preventive measures” against “enemy forces who would undermine ethnic unity” and stressed the need to preserve social stability.

Government officials and state media continued to accuse U.S.-exiled Uighur activist Rebiya Kadeer and her overseas followers of being behind the violence. She has denied the allegations and accused China of inciting the violence.