Chinese hackers have targeted computer systems of several US media companies this week in an apparent effort to spy on coverage of China.

The Wall Street Journal said Thursday its computers were hit by hackers, a day after The New York Times reported that its computer systems had been repeatedly infiltrated during the past four months since published an article which exposed the vast wealth amassed by a top Chinese leader’s family, reports AFP. The techniques used in the hacking were said to bear hallmarks used by the Chinese military in the past.

The Journal said the attacks were “for the apparent purpose of monitoring the newspaper’s China coverage” and said that Chinese cyberspying on US media “has become a widespread phenomenon”.

“Evidence shows that infiltration efforts target the monitoring of the Journal’s coverage of China, and are not attempt to gain commercial advantage or to misappropriate customer information,” a statement from Paula Keve of Journal publisher Dow Jones & Co said.

“We fully intend to continue the aggressive and independent journalism for which we are known,” Keve said.

On Wednesday, the New York Times reported that hackers had stolen reporters’ passwords and sought files that were part of a Times investigation into the $2 billion fortune of Premier Wen Jiaobao and his family.

CNN’s international service reportedly went down for several minutes after it ran a story on the hacking at the New York Times.

Chinese embassy spokesman Geng Shuang condemned the allegations, saying they were “irresponsible” and claimed they had no “solid proof and evidence”.

“The Chinese government prohibits cyberattacks and has done what it can to combat such activities in accordance with Chinese laws,” he said.