US search company Google has quietly dropped a warning message about online censorship in China shown to Chinese users when they search for politically sensitive phrases, according to a report on the online edition of Guardian.

Guardian said Google and Chinese authorities have been involved in a tense game of cat-and-mouse over the issue since May last year, but eventually Google has “reluctantly conceded defeat”.

Quoting unnamed Chinese sources, the report said the standoff “came to a head” in December, when Google finally decided it was "counterproductive" to continue the technical dispute, despite several attempts to get around it.

Google first launched its search function in China in 2006. In 2010, the US company pulled out of the Chinese mainland and moved its servers to Hong Kong.

Former US official, Google boss to go to DPRK next week

Former New Mexico governor Bill Richardson and Google chairman Eric Schmidt will head to Pyongyang next week on a "private humanitarian mission," Richardson's office said Saturday.

Richardson will hold a press conference at the airport in Beijing on Thursday, his office said in a statement, adding that no journalists would be accompanying the delegation.

The US State Department has voiced concerns about the trip, saying it was ill-timed in the wake of Pyongyang's rocket launch last month.

Richardson has said the trip is linked to the arrest late last year of a US citizen of Korean descent.

The former US ambassador to the United Nations has been to the Democratic People's Republic of Korea a number of times in the past 20 years and has been involved in negotiating the release of US citizens detained in the country.

Accompanying the pair will be Richardson's longtime aide, K.A. "Tony" Namkung, Jared Cohen, director of Google Ideas, a think tank run by the California-based Internet giant, and some staff, the statement said.

Richardson said Friday he hoped the trip would be "positive", and dismissed US concerns about the mission, saying it had already been postponed once at Washington's request and that the State Department should not be "nervous."

He stressed he and Schmidt would be traveling as private citizens, representing neither the US government nor Google.

"We will make an assessment and see what comes of our visit. I think it will be positive," Richardson told CNN.

"We're not representing the State Department, so they shouldn't be that nervous," he said in an earlier interview with CBS.

The son of Kenneth Bae, the detained American, contacted Richardson and asked for his assistance, the former governor said.

The US citizen, who was arrested in November, entered the country as a tourist according to DPRK's official Korean Central News Agency (KCNA), which said he had admitted committing a crime against the state.

The former New Mexico governor said while a meeting with DPRK leader Kim Jong-Un was "very doubtful," he expected to meet with several senior officials.