Apple Inc chief executive officer Tim Cook visited China for the second time in less than 10 months, attaching great importance to the world's biggest mobile phone market.

Cook met with Miao Wei, head of the Ministry of Industry and Information Technology, on Tuesday, and discussed the development of China's information technology industry, global mobile communications and Apple's business in China, according to a statement on the ministry's website.

Chinese media reported that Cook was seen smiling in front of China United Network Communications Group Co Ltd's building in Beijing on Wednesday morning.

"Cook was very satisfied on China Unicom's iPhone 5 handset sales," said an official from China Unicom, who asked not to be named.

China Unicom was the first telecom carrier on the Chinese mainland to offer Apple's iPhone handsets with a contract. The company began offering the iPhone 5 on Dec 14.

A micro blog from China Unicom confirmed Cook's visit on Wednesday afternoon, saying Cook and his colleagues met high-level management at China Unicom. "The meeting went pretty well," the micro blog said.

Some Beijing residents said on Sina Weibo that they saw Cook in Beijing's central business district and shared photos of him. Wearing a black coat, the gray-haired Cook seemed at ease and was very amiable.

"Cook's visit to China Unicom is more or less a polite gesture," Sandy Shen, a telecom analyst at Gartner China, told China Daily. The two sides have a relatively long history of cooperation, Shen said.

Rumors have circulated that the main reason for Cook's trip to China was to seek cooperation with China Mobile Ltd, the nation's biggest telecom operator, having a customer base of more than 700 million.

"There is a small chance that Apple and China Mobile will reach an agreement within six months, since China Mobile is sticking to a homegrown telecommunications standard that Apple does not support," Shen said.

She said she expects Apple to resolve the obstacle after China Mobile starts it commercial 4G TD-LTE rollout.

Li Jun, a spokesman for China Mobile Ltd, said he dose not have any information about whether China Mobile executives will meet Cook.

Apple's ranking in the Chinese smartphone market fell to No 6 in the third quarter, as the company faced tough competition from domestic rivals, according to the research firm International Data Corp.

Apple's market share by shipments in China was under 10 percent in the third quarter, slipping two notches from its position in the previous quarter, IDC said.

The Chinese smartphone market is growing rapidly, and some analysts say China has already replaced the United States as the world's biggest smartphone market by shipments.

The third quarter saw 60 million smartphones shipped in China, a record number and three times more than personal computer shipments, an IDC report showed.

Wang Ying, an analyst at Beijing-based Analysys International, said if Apple wants to expand further in China, it should extend its reach to third- and fourth-tier cities.

"Currently, most Apple fans live in major Chinese cities, but people in smaller cities have also shown an interest in Apple products."

Apple generated $5.7 billion in sales in China in the quarter ending in September and sold more than 2 million iPhone 5 handsets during the device's weekend debut in the country last month.

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