WASHINGTON (REUTERS) - A video feed of a Taiwanese minister was cut during US President Joe Biden's Summit for Democracy last week after a map in her slide presentation showed Taiwan in a different colour to China, which claims the island as its own.

Sources familiar with the matter told Reuters that Friday's (Dec 10) slide show by Taiwanese Digital Minister Audrey Tang caused consternation among US officials after the map appeared in her video feed for about a minute.

The sources, who did not want to be identified due to the sensitivity of the matter, said the video feed showing Ms Tang was cut during an ongoing panel discussion and replaced with audio only - at the behest of the White House.

The White House was concerned that differentiating Taiwan and China on a map in a US-hosted conference - to which Taiwan had been invited in a show of support at a time when it is under intense pressure from Beijing - could be seen as being at odds with Washington's one-China policy, which avoids taking a position as to whether Taiwan is part of China, the sources said.

The White House offered no formal comment, but the State Department said "confusion" over screen-sharing resulted in Ms Tang's video feed being dropped, calling it "an honest mistake".

"We valued Minister Tang's participation, which showcased Taiwan's world-class expertise on issues of transparent governance, human rights and countering disinformation," a spokesman said.

Ms Tang's presentation included a colour-coded map from South African non-governmental organisation Civicus, ranking the world by openness on civil rights.

Most of Asia was shown, with Taiwan coloured green, making it the only regional entity portrayed as "open", while all the others, including several US allies and partners, were labelled as being "closed", "repressed", "obstructed" or "narrowed". China, Laos, Vietnam and North Korea were coloured red and labelled "closed".

When the moderator returned to Ms Tang a few minutes later, there was no video of her, just audio, and a screenshot captioned: Minister Audrey Tang Taiwan.

An onscreen disclaimer later declared: "Any opinions expressed by individuals on this panel are those of the individual, and do not necessarily reflect the views of the United States government."

One source told Reuters the map generated an instant e-mail flurry among US officials, and the White House National Security Council (NSC) angrily contacted the State Department, concerned it appeared to show Taiwan as a distinct country.

Washington complained to Taiwan's government, which, in turn, was angry that Ms Tang's video had been cut.

The source called the US move an overreaction as the map was not inherently about national boundaries, but the NSC was also angry as the slide had not appeared in dry-run versions of the presentation before the summit, raising questions as to whether there was intentional messaging by Ms Tang and Taiwan.

"They choked," the source said of the White House reaction.

A second source directly involved in the summit said the video booth operator acted on White House instructions.

"It was clearly policy concerns," the source said, adding: "This was completely an internal overreaction."

The sources saw the move during a panel on countering digital authoritarianism as at odds with the summit's mission of bolstering democracy in the face of challenges from China and others.

They also said it could signal that the administration's support for Taiwan was not as "rock solid" as it has repeatedly stated.

Asked whether she believed the US government cut the video due to the slide, Ms Tang told Reuters in an e-mail: "No, I do not believe that this has anything to do with the Civicus map in my slides, or US allies in Asia for that matter."

Taiwan's Foreign Ministry blamed technical problems.

The issue comes at a highly sensitive time for US-Taiwan relations, when some Biden administration critics and foreign policy experts are calling for more overt shows of support for the island, including an end to a long-held policy of strategic ambiguity as to whether the US would defend it militarily.

Taiwan experts said they did not see the colour-coding of the map as a violation of unofficial US guidelines, which bar use of overt symbols of sovereignty, such as Taiwan's flag.

"It was clearly not to distinguish sovereignty, but the degree of democratic expression," said Mr Douglas Paal, a former unofficial US ambassador to Taiwan.