Rescuers search for victims in the debris of collapsed buildings Friday in China's Yingxiu Township. China struggled to bury its dead and help tens of thousands of injured and homeless Friday when a powerful aftershock brought new havoc four days after an earthquake.

Yingxiu, China ? A powerful aftershock knocked out roads and communications in some of the most quake-ravaged parts of central China on Friday, as emergency crews rescued 163 people who had survived up to 100 improbable hours trapped in the ruins.

As today dawned, rescuers were holding out hope of finding more survivors and authorities were preparing for the daunting task of housing and feeding millions left homeless.

With the official death toll at more than 22,000, an air force unit reached Yinchanggou, a scenic spot in the mountains north of the Sichuan provincial capital of Chengdu, finding landslides had swept away rustic small hotels.

“There are several hundred hotels, including farmer homestays, probably 800 in all. They are all rubble now,” Cai Weisu, an official with an air force unit from the Chengdu Military Region, told Sichuan Television. Most of the dead are tourists, he said, but did not identify whether they were foreign or Chinese.

Tens of thousands of people are considered buried or missing throughout the disaster zone. There were about 12 million people living within a 60-mile radius of the epicenter of Wenchuan, according to a study on the potential impact of the quake by Xu Mingbao, a senior researcher at the University of Michigan’s China Data Center.

Acutely aware its response to China’s worst disaster in 30 years could affect Beijing’s image heading into the Olympic Games, President Hu Jintao ramped up the government’s public relations efforts, making his first trip to the stricken region.

And in response to swelling anger, government officials accustomed to tightly controlled media took the unusual step of fielding questions from people online about why thousands of schools that collapsed were not built to be quake-safe.

Damage from the magnitude-5.5 aftershock – one of dozens of strong tremors since the devastating quake Monday – was a temporary setback to the mammoth relief operation. Repair crews were rapidly restoring mobile phone services and unblocking roads within four hours, state media reported.

Trucks navigated around boulders and splintered pavement that clogged roads into the forest-clad mountains of Beichuan county.