An earthquake registering 7.8 on the Richter Scale knocked out mobile phone service in the western Chinese city of Chengdu, although fixed-line networks remained in service, Chinese state television reported Monday afternoon.

Mobile phone service in Chengdu, the capital of Sichuan province, was not available because of the earthquake, a representative of the Sichuan Earthquake Bureau told China Central Television (CCTV) in a live telephone interview. He did not specify whether the networks of both China Mobile, the nation's and world's largest mobile carrier, and China Unicom, China's other major mobile carrier, were affected.

A CCTV reporter in Chengdu confirmed that mobile service was not available, but that fixed-line service from Chengdu was still operating, as he called CCTV's studios in Beijing from a public phone. CCTV advised people watching in the area to remain calm and not jam phone lines with calls to family and friends.

A representative from China Mobile said he had no information yet, and declined to give his name.

The semiconductor industry and China's growing software outsourcing industry take advantage of Chengdu's status as China's fifth-largest city and southwest China's largest academic center.

Although the Chengdu region is not considered a major manufacturing center for semiconductors, Intel began semiconductor manufacturing there in 2005, and employs 600 at a testing and assembly facility in Chengdu.

"We are now determining if this has implications for Intel's operation in Chengdu. Our first priority is the safety of our people," said Danny Cheung, an Intel spokesman based in Singapore, in an e-mail.

Semiconductor Manufacturing International (SMIC) also operates a testing and assembly facility there, according to its Web site. Sources said that SMIC evacuated a fabrication plant and halted production as a result of the quake.

The earthquake occurred at 2:28 p.m. Beijing local time. The State Seismological Bureau (SSB) originally reported the quake registered at 7.6 on the Richter Scale, but later upgraded it to 7.8. The epicenter was approximately 55 kilometers (33 miles) northwest of Chengdu in Wenchuan County. Shaking lasted for approximately one minute, dislodging lights from ceiling fixtures and knocking over water coolers, a reporter told CCTV.

CCTV did not report aftershocks, but the U.S. Geological Service's Web site recorded two. The quake was felt as far away as coastal Zhejiang province and Beijing. Beijing experienced a separate 3.9 earthquake at 2:35 p.m., the SSB confirmed.

CCTV's first pictures of the event, broadcast at 4:23 p.m. Beijing time, showed people talking on mobile handsets, although it is not known which networks they were using at the time. They showed traffic moving in the street, and a woman with her head bleeding getting into a car. There was no other immediate evidence of damage or injuries in the footage.