In a speech that took aim at China on Thursday, Pence said the Dragonfly project — first reported by The Intercept — would speed up efforts by Beijing to impose more censorship on its citizens.
The Wall Street Journal quoted Pence as telling the Hudson Institute, a conservative Washington think-tank: "Google should immediately end development of the Dragonfly app that will strengthen Communist Party censorship and compromise the privacy of Chinese customers."
There have also been reports that managers at the company were trying to shut down access to any material connected to the project.
Another report said that engineers had used search queries from a Chinese Web directory service owned by Google to develop blacklists for the censored search engine.
The WSJ quoted a Google spokeswoman as refusing to comment on Pence's speech and referring the newspaper to a previous statement issued by the company which claimed work on a China search engine was "exploratory" and that Google was “not close to launching a search product in China".
The Dragonfly project is said to have started after Google chief executive Sundar Pichai held discussions with Wang Huning, a senior figure in the Chinese Communist Party, in December 2017. Work was begun during the Western spring of 2017 and was fast-tracked after the Pichai-Huning meeting.
After the meeting with Huning, Google decided to open an artificial intelligence research centre in Beijing. In May 2018, a Google file management app was released for Chinese Internet users. And in July, Google released a “Guess The Sketch” game on WeChat, the main Chinese messaging and social media platform.
Programmers created a customised Android search app with different versions known as Maotai and Longfei and these had been demonstrated to Chinese government authorities.
Since The Intercept's first report, Google has made no public statement about the project, though it has been asked for a statement on more than a dozen occasions.
The final version of the app is expected to be launched in the next six to nine months, provided approval is granted by Beijing.
Google had a censored search engine operating in China from 2006 to 2010, but quit the country after its servers were hacked.