China kept the pressure on Google Thursday, accusing it again of illegally spreading pornographic content following reports the US giant's English-language website was inaccessible for hours.

"We have found that Google has spread a lot of pornographic content, which is a serious violation of Chinese laws and regulations," foreign ministry spokesman Qin Gang told reporters.

"Google is an Internet enterprise providing services in China and should earnestly abide by Chinese laws and regulations," he said, adding he had no specific details on the recent outage.

Google promised last week to work harder to eliminate pornography from its Chinese Web searches after a government Internet watchdog levelled similar accusations against the firm, saying it had continued to allow such results to be displayed.

On Wednesday night, the search engine's main English-language website was inaccessible for over two hours in China, the official China Daily newspaper reported, adding that its Chinese-language website google.cn was unaffected.

China blocks Internet content it deems unhealthy, which has included pornography and information critical of the government, a censorship system dubbed the "Great Firewall of China."

Computer makers were notified by the government recently that all personal computers sold from July 1 must be shipped with anti-pornography software, a move that has led to widespread censorship fears both inside and outside China.

China has the world's largest online population at nearly 300 million Web users, and the country's Communist Party rulers have struggled to control a proliferation of online content in recent years.

Qin said China had noted Google's pledge to work at eliminating the spread of pornographic content.

"We hope that this issue will be dealt with as soon as possible," he said.